Kiranjeet Gill, M.D., Daniel J. Deziel, M.D.
1 Which of the following statements about the anatomy of the liver is true?
A The right lobe extends to the umbilical fissure and falciform ligament.
B The left lobe end at the falciform ligament.
C The quadrate lobe is a portion of the medial segment of the right lobe.
D The left lobe contains the anterior and lateral segments.
E The lateral segment of the left lobe in the American system consists of segments II and III.
Ref.: 1-3
Comments
The surgical anatomy of the liver is based on the distribution of the hepatic veins and portal structures and has been modified several times. There are two main anatomic classification systems for the liver, the American system and the French system. In both these systems, the liver is divided into right and left lobes by the Cantilie line, a longitudinal plane that extends from the gallbladder fossa to the inferior vena cava. This plane, also called the portal fissure, contains the middle hepatic vein and the bifurcation of the portal vein. In the American system, the liver is further broken down into four segments, with each lobe containing two segments. The right lobe of the liver consists of posterior and anterior segments. The left lobe consists of a medial segment (quadrate lobe) and a lateral segment divided by the falciform ligament. The caudate lobe can be considered anatomically independent of the right and left lobes because it receives portal and arterial blood supply from both sides and has venous drainage directly into the inferior vena cava.
In the French system, developed by C. Couinaud, the two lobes of the liver are broken down into eight segments. These eight segments are formed by three vertical planes (scissurae) created by the right, middle, and left hepatic veins, which results in four sectors. These four sectors are further divided by a plane created by the branching portal system. Therefore, the left lobe, according to the French system, is divided into medial and lateral segments by the left hepatic vein. The lateral sector of the left lobe consists of a superior segment (II) and an inferior segment (III). The medial sector of the left lobe is segment IV. The right lobe consists of anteromedial and posterolateral sectors divided by a vertical plane containing the right hepatic vein. The anteromedial sector is made up of segment V (inferior) and segment VIII (superior), and the posterolateral sector is made up of segment VI (inferior) and segment VII (superior).
Answer
E
2 Which of the following statements is true about the hepatic arterial supply?
A Aberrant hepatic arterial anatomy is present in less than 5% of all patients.
B The cystic artery is usually a branch off the proper hepatic artery.
C A “replaced” right hepatic artery arises from the superior mesenteric artery.
D The hepatic artery provides 75% of blood flow to the liver.
E The hepatic artery lies dorsal to the portal vein within the hepatic hilum.
Ref.: 1-3
Comments
The hepatic arterial supply is normally derived from the celiac axis by way of the common hepatic artery, which becomes the proper hepatic artery after giving off the gastroduodenal branch and subsequently bifurcates into right and left hepatic branches. The hepatic artery lies ventral to the portal vein. The middle hepatic artery is usually a branch off the left hepatic artery, and the cystic artery is generally a branch off the right hepatic artery. There is, however, significant variability in hepatic arterial anatomy in up to 50% of patients. In approximately 15% of individuals, the right hepatic artery arises from the superior mesenteric artery (replaced right hepatic artery) and is found in the right dorsal border of the hepatoduodenal ligament. In roughly 10% of individuals, the left hepatic artery originates from the left gastric artery and is located in the gastrohepatic ligament. These commonly encountered variants can have important surgical implications during upper abdominal operations. The arterial blood supply accounts for only 25% of hepatic blood flow, with the remainder being supplied by the portal vein.
Answer
C
3 Which of the following statements about the anatomy of the hepatic veins is true?
A The left hepatic vein drains the entire left lobe.
B Veins from the caudate lobe enter the inferior vena cava directly.
C The middle hepatic vein usually drains into the right hepatic vein.
D There are valves in the hepatic venous system.
E Hepatic veins have prominent hyperechoic walls on ultrasound imaging.
Ref.: 1-4
Comments
The hepatic veins begin in the liver lobules as the central veins and coalesce to form the right, left, and middle hepatic veins, which drain into the inferior vena cava and are of considerable surgical importance because they define the three vertical scissurae of the liver. The right vein, which is generally the largest, drains most of the right lobe. The left vein drains the lateral segment of the left lobe and a portion of the medial segment as well. The middle vein drains the inferoanterior portion of the right lobe and the inferomedial segment of the left lobe. This vein joins the left hepatic vein in 80% of individuals and enters the inferior vena cava directly in the remainder. There are also smaller veins, particularly those draining the caudate lobe dorsally, that enter directly into the inferior vena cava. The human hepatic venous system has no valves. The portal veins and hepatic veins can readily be differentiated from each other on the basis of their distinctive sonographic features. The portal veins (not the hepatic veins) have prominent hyperechoic walls.
Answer
B
4 Which of the following statements is true about the portal vein?
A It is formed by the junction of the inferior mesenteric vein and splenic vein.
B It is the most dorsal structure in the hepatoduodenal ligament.
C It contains the valves of Mirizzi.
D The right portal vein typically branches later than the left portal vein.
E It carries deoxygenated blood and provides only 10% of the liver’s oxygenation
Ref.: 1-3
Comments
The portal vein is usually formed dorsal to the neck of the pancreas by the junction of the superior mesenteric vein and splenic veins. It ascends posterior to the common bile duct and hepatic artery in the hepatoduodenal ligament. These three structures make up the portal triad. There are no valves in the portal venous system (Pablo Mirizzi described valves in the common hepatic duct that do not exist). The portal vein bifurcates just outside the liver. The right portal vein has anterior and posterior branches that typically diverge only a short distance from the bifurcation and then quickly dive into the liver parenchyma. The left portal vein has a longer transverse portion (pars transversus) and then angulates anteriorly in the umbilical fissure (pars umbilicus), where it gives off medial branches to segment IV and lateral branches to segments II and III. The portal vein provides approximately 75% of hepatic blood flow, and although the blood is largely deoxygenated, it provides up to 50% to 70% of the liver’s oxygenation secondary to the portal system’s large volume flow rate.
Answer
B
5 Which of the following hepatic resections involves dissection in the plane of the falciform ligament or umbilical fissure?
A Right lobectomy
B Right trisegmentectomy
C Left lobectomy
D Left lateral segmentectomy
E None of the above
Ref.: 1-3
Comments
Hepatic resections can be broken down into (1) anatomic resections, (2) nonanatomic resections (wedge resections), and (3) enucleation procedures. Anatomic resections are based on either the American or the French segmental system. Right lobectomy includes segments V, VI, VII, and VIII. Right trisegmentectomy also includes segment IV. Left lobectomy includes segments II, III, and IV. Left lateral segmentectomy includes only segments II and III. The umbilical fissure is the segmental plane between the medial and lateral segments of the left lobe of the liver. A portion of the left branch of the portal vein, known as the pars umbilicus, runs in the inferior portion of the umbilical fissure. Dissection is therefore never carried out directly in the segmental fissure. During left lateral segmentectomy, the plane of the parenchymal dissection is to the left of the fissure, whereas with right trisegmentectomy, the parenchyma is divided to the right of the fissure. Both right and left lobectomies involve dissection well to the right of this plane.
Answer
E
6 Which of the following characteristics is typically seen on ultrasound imaging of the hepatic portal vein branches?
A Hyperechoic vessel walls
B Hepatofugal blood flow
C Diastolic reversal of blood flow
D Location between hepatic segments
E Vertical orientation
Ref.: 4
Comments
The portal veins and hepatic veins can readily be differentiated from each other on the basis of their distinctive sonographic features. The portal vein and its branches have prominent hyperechoic walls. This appearance has been attributed to the accompanying intrahepatic branches of the hepatic artery and bile duct, which are not generally seen individually on external ultrasound imaging. In contrast, the hepatic veins appear to be essentially “wall-less.” They are anechoic or hypoechoic tubular structures that are vertically oriented and increase in caliber as they course toward the inferior vena cava. The portal veins are more transversely oriented and of larger caliber centrally. The portal vein branches are located within the anatomic liver segments, and the hepatic veins are found between the segments. Doppler ultrasound permits characterization of flow patterns in the hepatic vessels. Under normal circumstances, portal vein flow is toward the liver (hepatopedal). Flow in the portal vein is usually of fairly low velocity, with minor undulations and continued forward flow during diastole. Flow in the hepatic veins is hepatofugal and varies according to the cardiorespiratory cycle. The portal veins are horizontally oriented, whereas the hepatic veins are vertically oriented.
Answer
A
7 A 40-year-old woman arrives at the emergency department complaining of right upper abdominal pain. Her vital signs and laboratory values are normal; however, ultrasound demonstrates a hyperechoic liver with a geographic hypoechoic area adjacent to the gallbladder. What does this finding probably represent?
A Duplication of the gallbladder
B Reverberation artifact
C Focal fatty sparing
D Hepatic abscess
E Bowel gas
Ref.: 4
Comments
Fatty infiltration of the liver is a common finding that produces a hyperechoic parenchymal pattern on ultrasound. It is not unusual to have focal areas of fatty sparing within an otherwise steatotic liver. These areas typically appear as zonal hypoechoic regions and are usually found adjacent to the gallbladder or anterior to the porta hepatis. Duplication of the gallbladder is a rare occurrence. Reverberation artifacts are echoes within cystic structures. The sonographic appearance of hepatic abscesses is variable, depending on the cause and duration. Pyogenic abscesses are usually complex, with cystic characteristics and internal echoes caused by debris or septations. Bowel gas is highly reflective and impedes ultrasound imaging.
Answer
C
8 Which of the following is true regarding the hepatic functional unit?
A The center of the hepatic lobule is the portal triad.
B Blood flows from the hepatic vein to the portal triad.
C Zone III is the most susceptible to hypoxic injury.
D Hepatocytes in zone I have the lowest oxygen tension.
E Bile flows toward the centrilobular hepatic venule.
Ref.: 1, 3
Comments
The functional histologic unit of the liver is the acinus. At the center of the acinus is the portal triad, which consists of a terminal branch of the portal vein (portal venule) along with a hepatic arteriole and bile ductule. Blood from the terminal portal venule goes into the hepatic sinusoids, around which hepatocytes are located. Eventually, the blood returns to the central vein leading to the terminal hepatic venules at the periphery of the acinar unit. The hepatocytes of the acinus are divided into three zones, with zone I being closest to the afferent portal venule and zone III being nearest the efferent central hepatic venule. Zone II is between these two points. Within the acinus, there is a gradient of solute concentration and oxygen tension that is greatest near the portal venules at the center of the acinus. The hepatocytes in zone I are therefore exposed to more oxygen and are less subject to hypoxia than are the hepatocytes near the periphery of the acinus (zone III). This explains the histologic pattern of centrilobular necrosis that occurs following ischemia. The hepatic venule is at the center of the histologic hepatic lobule. Each hepatic lobule is thus surrounded by several peripheral acini. Bile is formed within the hepatocytes and empties into terminal canaliculi, which coalesce into bile ducts. The bile then flows toward the portal triad.
Answer
C
9 Alkaline phosphatase is primarily located in which portion of the hepatocyte plasma membrane?
A Sinusoidal membrane
B Basolateral membrane
C Canalicular membrane
D Basement membrane
E None of the above
Ref.: 1, 3
Comments
The plasma membrane of the hepatocyte has different regions, or domains, with ultrastructures designed for various functions. The sinusoidal membrane is the domain that borders the perisinusoidal space of Disse. It is covered with microvilli that project into the perisinusoidal space. These microvilli increase the absorptive area in contact with sinusoidal blood and allow proteins, solutes, and other substances to be transported across this border of the hepatocyte. The flat basolateral membrane connects the adjacent hepatocytes and is important for attachment and cellular interactions. The canalicular membrane is a specialized section of the hepatocyte membrane that is involved in bile formation and the transport of various substances into bile. The canalicular regions are separated from the pericellular space by tight junctions. The canalicular membrane contains enzymes such as alkaline phosphatase and 5′-nucleotidase. Thus, high levels of alkaline phosphatase are noted with extrahepatic bile duct obstruction.
Answer
C
10 During fasting, the liver provides energy substrates by all but which of the following mechanisms?
A Glycogenolysis
B Glycolysis
C Gluconeogenesis from alanine
D Gluconeogenesis from lactate
E Formation of ketone bodies from fatty acids
Ref.: 1, 3, 5
Comments
The liver plays a pivotal role in energy metabolism. In the fed state, glucose is converted to glycogen for storage. The liver itself obtains its energy primarily from ketoacids rather than glucose, although it can use glycolysis during periods of glucose excess (fed state). During fasting, the liver provides glucose by breakdown of the stored glycogen (glycogenolysis). Glucose is a critical energy source for red blood cells, the central nervous system, and the kidneys. Because glycogen stores are depleted after about 48 hours, the liver generates glucose from other sources. Alanine, other amino acids, lactate, and glycerol can serve as carbon sources for gluconeogenesis. Lipolysis occurs during prolonged fasting, and the fatty acids released from adipose stores are oxidized in hepatocytes to form ketone bodies. Ketone bodies are an important alternative fuel source for brain and muscle.
Answer
B
11 The reticuloendothelial function of the liver is primarily dependent on which of the following cells?
A Hepatocytes
B Kupffer cells
C Histiocytes
D Ito cells
E All of the above
Ref.: 1, 3, 5
Comments
The reticuloendothelial system (RES) functions to clear the circulation of particulate matter and microbes. The RES consists of fixed phagocytic cells located primarily in the liver, spleen, and lungs. Kupffer cells are responsible for the reticuloendothelial function of the liver. Located along the lining of the hepatic sinusoids (along with the sinusoidal endothelial cells), they are uniquely positioned to phagocytize and process gut antigens from the splanchnic and systemic circulation. Kupffer cells play an important role in the production and control of various cytokines and inflammatory regulators. Histiocytes are macrophages in connective tissue. Ito cells, also call hepatic stellate cells, are perisinusoidal cells involved in collagen and vitamin A metabolism.
Answer
B
12 Which of the following proteins is not primarily synthesized in the liver?
A Albumin
B Fibrinogen
C von Willebrand factor
D Transferrin
E Factor VII
Ref.: 1, 3, 5
Comments
The liver is the primary or sole source of numerous plasma proteins, including albumin, α-globulins, and an array of other transport proteins such as transferrin, hepatoglobulin, ferritin, and ceruloplasmin. Eleven proteins involved in hemostasis are synthesized in the liver, including fibrinogen (factor I); the vitamin K–dependent factors (II, VII, IX, and X); and all of the procoagulation factors except for von Willebrand factor, which is synthesized by vascular endothelial cells. Because factor VII has the shortest half-life, 5 to 7 hours, measurements of factor VII levels are useful for determining liver failure.
Answer
C
13 The cytochrome P-450 system transforms compounds by all of following mechanisms except?
A Oxidation
B Hydrolysis
C Conjugation
D Reduction
E Both A and C
Ref.: 1, 3, 5
Comments
The liver is responsible for biotransformation of many endogenous and exogenous substances. For the most part, this process detoxifies potentially injurious substances and facilitates their elimination. In some instances, however, hepatic biotransformation produces more toxic metabolites. There are two general mechanisms by which the liver accomplishes biotransformation: oxidation, reduction, and hydrolysis (phase I reactions) and conjugation (phase II reactions). The cytochrome P-450 enzyme system catalyzes phase I reaction. The second mechanism involves an array of enzymes that conjugate substances with other endogenous molecules. These reactions are referred to as phase II reactions, and their purpose is to convert hydrophobic compounds to hydrophilic ones that are water soluble and can thus be eliminated in bile or urine. The liver is also the principal site of conversion of ammonia to urea via the urea cycle, which is a separate process.
Answer
C
14 The liver is integral to which of the following steps in vitamin D metabolism?
A Intestinal absorption
B 1-Hydroxylation
C 25-Hydroxylation
D Formation of cholecalciferol
E Both A and C
Ref.: 1, 3
Comments
The liver is integral to metabolism of the fat-soluble vitamins A, D, E, and K. Each of these vitamins requires fatty acid micellization for adequate intestinal absorption, which requires the bile salts made in the liver. The liver is not only integral to the intestinal absorption of vitamin D but also plays an active role in one of its activation steps, 25-hydroxylation. Vitamin D is either produced in the skin when 7-dehydrocholestrol reacts with ultraviolet B light to form cholecalciferol or is ingested. As already mentioned, the liver aids in intestinal absorption via fatty acid micellization. Once in the liver, vitamin D undergoes 25-hydroxylation. It then undergoes 1-hydroxylation in the kidneys to arrive at its metabolically active form, which is important in the homeostasis of calcium and phosphorus.
Answer
E
15 In a patient with obstructive jaundice, which of the following enzymes is usually elevated?
A Alkaline phosphatase
B Leucine aminopeptidase
C γ-Glutamyltransferase (GGT)
D 5′-Nucleotidase
E All of the above
Ref.: 1
Comments
Aspartate transaminase (AST, formerly serum glutamic oxaloacetic transaminase [SGOT]), alanine transaminase (ALT, formerly serum glutamate pyruvate transaminase [SGPT]), and lactate dehydrogenase (LDH) are indicators of the integrity of the cell membrane, and elevated levels reflect hepatocyte injury with leakage. Levels of these enzymes are usually only mildly or moderately elevated in pure obstructive jaundice. Other enzymes, including alkaline phosphatase, 5′-nucleotidase, leucine aminopeptidase, and GGT, reflect the excretory capacity of the liver. Levels of these enzymes are typically elevated in the presence of extrahepatic bile duct obstruction or intrahepatic cholestasis. Elevations are also seen in patients with hepatic parenchymal disease or liver tumors. Transferrin and albumin levels decrease with liver disease because they reflect changes in liver function and nutritional status.
Answer
E
16 Which of the following operative techniques limits blood loss during major hepatic resection?
A Portal triad clamping
B Normothermic total hepatic vascular isolation
C Total hepatic vascular isolation with venovenous bypass
D Anesthesia with low central venous pressure
E All of the above
Ref.: 6, 7
Comments
Hemorrhage is one of the major hazards during liver resection. Troublesome bleeding is most likely to occur during division of the hepatic parenchyma, and life-threatening hemorrhage is most commonly from the hepatic veins and their branches. A variety of intraoperative techniques have been used in an effort to avoid this problem. A disadvantage of any vascular occlusion, however, is the potential for ischemic injury to the liver, particularly in patients with underlying hepatocellular disease. Occlusion of the portal triad (Pringle maneuver) can be useful for limiting bleeding from the hepatic artery and portal vein branches. It has generally been suggested that periods of occlusion should not exceed 20 minutes and perhaps should be shorter. Total hepatic vascular isolation requires occlusion of the inferior vena cava above and below the liver, in addition to the Pringle maneuver. Such management can be complex and is not well tolerated by some patients. Venovenous bypass, which has commonly been used during hepatic transplantation, has also been applied to major hepatic resections at some centers. Attempts to protect the liver during vascular occlusion via local hepatic hypothermia or systemic steroids have not been uniformly practiced or successful. Anesthesia with low central venous pressure minimizes hepatic venous bleeding by fluid restriction, head-down positioning, and the vasodilatory effects of standard anesthetics. Low–central venous pressure anesthesia during major hepatic resection decreases the need for perioperative blood transfusion. This technique has been accomplished with low rates of mortality and postoperative renal compromise.
Answer
E
17 Resection of hepatic metastases has most clearly benefited patients with which of the following cancers?
A Colon
B Breast
C Stomach
D Pancreas
E Lung
Ref.: 1-3
Comments
Resection of hepatic metastases from colorectal cancer provides a clear survival advantage over any other treatment and should be performed whenever possible. The 5-year survival rate is approximately 25% and is as high as 40% in favorable subgroups. Resection of metastatic neuroendocrine tumors (e.g., carcinoid, insulinoma, and gastrinoma) can be valuable for controlling the symptoms of excessive endocrine secretion. Experience with hepatic resection for metastases from other portal sites (e.g., stomach, pancreas, and biliary) or nonportal sites (e.g., lung, breast, melanoma, gynecologic, head and neck, and renal) has been more limited, and the results have not generally been as encouraging. Occasionally, a patient with a noncolorectal primary malignancy is cured when the isolated hepatic metastasis is resected. However, the natural history of noncolorectal primary malignancies is such that metastases isolated to the liver rarely develop. Hepatic resection for direct, contiguous growth of the primary tumor (e.g., stomach and biliary) into the liver sometimes produces long-term survivors.
Answer
A
18 A 50-year-old woman is incidentally found to have a 4-cm hepatic cyst with no internal echoes on ultrasound imaging. Which of the following would be the most appropriate management?
A Observation of the cyst
B Tamoxifen to prevent enlargement
C Resection because of the risk for hemorrhage
D Percutaneous aspiration for cytologic study
E Magnetic resonance imaging (MRI) for further characterization of the cyst
Ref.: 1, 3, 5
Comments
Simple, nonparasitic hepatic cysts are presumed to be congenital. They may be single or multiple, are more common in women, and are usually asymptomatic. The absence of internal echoes is diagnostic of a simple rather than a complex cyst, a cystic neoplasm, or a solid lesion. No further intervention is indicated for asymptomatic liver cysts when the diagnosis is secure, which can be ascertained by ultrasound, computed tomography (CT), or MRI. If the diagnosis of a simple cyst is made by ultrasound, there is no need to perform MRI. Complications such as hemorrhage or infection are rare, and these lesions are not premalignant. Exogenous hormones are not recognized to be harmful, nor is antihormonal therapy indicated. Occasionally, large cysts are symptomatic, primarily secondary to local pressure, which may cause biliary obstruction. Treatment of symptomatic cysts is operative resection or unroofing. This may be performed via an open or laparoscopic technique. Percutaneous drainage or injection of alcohol or other sclerosing agents does not suffice and is not recommended. If the cyst is found to communicate with the bile ducts, either excision or Roux-en-Y cystojejunostomy may be performed.
Answer
A
19 A 30-year-old Hispanic man visiting from Mexico comes to the emergency department with a history of 2 weeks of right upper quadrant pain and tenderness, fevers, chills, and diarrhea. He is febrile to 102.9° F. His heart rate and blood pressure are 120 beats/min and 100/75 mm Hg, respectively. Laboratory results include a white blood cell count of 16,000/mm3, AST of 50 IU/L, and ALT of 93 IU/L. Ultrasound of the abdomen shows a 4 × 7-cm round, hypoechoic, nonhomogenous lesion abutting the liver capsule without rim echoes. Subsequent CT also demonstrates a non–rim-enhancing hypoechoic lesion with a smaller adjacent lesion measuring 2 × 2 cm. Which of the following is the most appropriate course of action?
A Observation
B Open surgical drainage
C Broad-spectrum antibiotics and percutaneous drainage
D Serologic testing for Entamoeba histolytica and oral metronidazole
E Therapeutic fine-needle aspiration
Ref.: 1, 2
Comments
The clinical signs and symptoms of pyogenic (bacterial) and amebic liver abscesses may be similar and consist predominantly of fever and pain, but it is important to differentiate between the two for therapeutic purposes. Escherichia coli or other gram-negative bacteria are the organisms most commonly isolated from pyogenic abscesses. Streptococcus spp. and anaerobes such as Bacteroides are also common. Today, the most frequent source of pyogenic abscess is contiguous infection in the biliary tract, such as cholangitis. Other sources include infectious foci within the portal venous drainage system, direct extension from perihepatic sites, and hematogenous spread. The right lobe is the most commonly involved, which has been attributed to a streaming effect on the portal vein. Approximately 20% of pyogenic abscesses are cryptogenic. The diagnosis is based on the clinical findings and hepatic imaging and may be confirmed by fine-needle aspiration. Treatment of pyogenic abscess requires eradication of both the abscess and the source. Treatment of the abscess usually requires drainage by operative or percutaneous approaches. Antibiotic therapy alone may suffice for the treatment of multiple small abscesses.
Amebic abscesses are caused by the protozoan E. histolytica, which is spread through the fecal-oral route. Once ingested, the cysts pass into the intestines, where the trophozoite is released and transmitted to the colon. These trophozoites can then invade the colonic mucosa and subsequently reach the liver via the portal vein. In the liver, these trophozoites produce a liquefaction necrosis responsible for the classic “anchovy paste” appearance. Protozoa are not usually isolated from the abscess because they are located in the peripheral rim of tissue. Diagnosis requires hepatic imaging (usually ultrasound or CT) and serologic testing for the presence of E. histolytica antibodies, as well as a thorough history and physical examination. The patient in this question is a young man from an endemic region who has signs and symptoms similar to those of a pyogenic liver abscess; however, his classic history and the lack of rim enhancement on imaging suggest the diagnosis of amebic abscess rather than pyogenic abscess. Hepatic amebiasis is treated primarily by the administration of amebicidal drugs, with metronidazole being the drug of choice. Percutaneous aspiration may be indicated if the patient does not respond to medical management or the diagnosis is in question. Percutaneous or operative drainage is also indicated in the presence of secondary bacterial infection, which occurs in about 10% of amebic abscesses.
Answer
D
20 A 50-year-old woman complains of a 4-month history of right-sided abdominal pain and nausea. Her vital signs are stable and she is afebrile. Her physical examination is unremarkable except for hepatomegaly. Ultrasound of the abdomen shows an 8-cm well-circumscribed cyst with a rosette appearance. What is the preferred treatment of this patient?
A Pericystectomy
B Percutaneous catheter drainage
C Transperitoneal surgical drainage
D Metronidazole
E Albendazole
Ref.: 1
Comments
The helminth Echinococcus granulosus is responsible for most hydatid diseases of the liver. It is usually a unilocular process involving the right lobe, although it may be manifested as multiple cysts. Complications include intrabiliary, intraperitoneal, or intrapleural rupture; secondary infection; anaphylaxis; and mass replacement of the liver. These lesions often have a calcified wall and can be diagnosed serologically by indirect hemagglutination tests, complement fixation tests, serum immunoelectrophoresis, and formerly, the Casoni skin test. CT and ultrasound may demonstrate characteristic daughter cysts (hydatid sand) or granddaughter cysts (rosette appearance) within the cyst. Treatment is primarily surgical. Percutaneous aspiration or drainage is generally contraindicated because of the risk for intraperitoneal dissemination; however, since the advent of chemotherapeutic agents such as albendazole, some clinicians have proposed percutaneous drainage. The principles of surgical therapy are to avoid spillage and remove the entire germinal layer. The cyst consists of an inner germinal layer (endocyst) and an outer fibrous membrane layer (pericyst). Resection is usually accomplished by pericystectomy. Anatomic hepatic resection is not generally required but may be used. Surgery in addition to preoperative and postoperative benzimidazole compounds have been shown to be very effective. Metronidazole is used for the treatment of amebic liver abscesses. Because 20% of echinococcal cysts exhibit biliary communication, assessment by preoperative endoscopic retrograde cholangiopancreatography or intraoperative cholangiography is important in any patient with jaundice, cholangitis, elevated liver enzyme levels, or bile noted during resection. Scolicidal agents should be used with caution because of the risk of sclerosing the bile ducts in the event that the agent finds its way into the ductal system.
Answer
A
21 A 28-year-old asymptomatic, white woman is incidentally found to have a 3.5-cm hypervascular lesion with a central scar in the right lobe of her liver. On delayed images there is increased uptake of contrast material in the scar in comparison with the surrounding liver parenchyma. She is otherwise healthy and takes no medications. Liver enzyme and α-fetoprotein levels are within normal limits. Which of the following is the most appropriate management of this patient?
A Open liver resection
B Open surgical biopsy
C Observation
D Chemoembolization
E Hepatic artery embolization
Ref.: 1-3, 5
Comments
This patient has focal nodular hyperplasia (FNH), which is often found incidentally on imaging or during laparotomy. FNH is a benign liver tumor that predominantly occurs in women in the third to fifth decades of life. It is similar to hepatic adenoma (HA), but with important differentiating clinical and histologic features and therapeutic implications. Both occur most commonly in women of childbearing age; however, HA is associated with the use of oral contraceptives and anabolic steroids and is also seen in certain glycogen storage diseases. HA is usually symptomatic (80% of cases) and is associated with rupture and bleeding in a substantial proportion of patients, whereas FNH is usually asymptomatic and found incidentally. Furthermore, HA has potential for malignant transformation, whereas the risk for malignancy in FNH is unlikely but uncertain. Histologically, HA consists of hepatocytes without bile ducts or Kupffer cells. FNH contains Kupffer cells along with a central stellate scar surrounded by fibrous tissue. Scanning for Kupffer cell activity with technetium-99m (99mTc)-labeled sulfur colloid is thus useful in differentiating the lesions. Because of the asymptomatic nature of this patient, small size of the lesion, and negligible risk for malignant transformation, observation is appropriate. Surgical resection is reserved for symptomatic patients or when the diagnosis is uncertain.
Answer
C
22 Right upper quadrant abdominal pain develops in a 25-year-old woman taking oral contraceptives. CT demonstrates a hypodense, 6-cm mass in the right lobe of the liver. A 99mTc-labeled scan reveals a defect in the area of the mass. Angiography reveals a hypervascular tumor with a peripheral blood supply. Which of the following is the appropriate management?
A Discontinuation of oral contraceptives and observation with serial CT
B Percutaneous needle biopsy
C Hepatic resection
D Arterial embolization
E Radiation therapy
Ref.: 1-3, 5
Comments
The imaging characteristics described are typical of hepatic adenoma. Because HA does not contain Kupffer cells, it does not take up radioisotope. This point may be useful for differentiating HA from FNH but not necessarily from other mass lesions of the liver. Percutaneous biopsy of suspected HA is not advisable because of the risk for hemorrhage. HAs associated with oral contraceptives tend to be larger and have a higher risk for bleeding. Regression does not reliably occur with cessation of oral contraceptives. However, for lesions smaller than 4 cm, a trial of cessation of contraceptives or steroids with observation may be attempted. Resection is indicated for most suspected HAs, particularly for symptomatic lesions, for patients not taking oral contraceptives, and if the diagnosis is uncertain. Embolization may be useful for treating hemorrhage in a patient whose HA is inoperable. Radiation has no role in the management of HA.
Answer
C
23 An asymptomatic 45-year-old woman is found to have a 4-cm liver mass. CT demonstrates an initial hypodense lesion with peripheral-to-central enhancement by contrast material. MRI shows a dense T2-weighted phase. Which of the following is the appropriate management?
A Arteriography
B Observation
C Percutaneous needle biopsy
D Resection
E Radiation therapy
Ref.: 1-3, 5
Comments
Hemangiomas are the most common benign liver tumors and occur in 7% of the population. They are characterized by collections of dilated blood vessels that can be diagnosed by their appearance on noninvasive imaging studies. Contrast-enhanced CT reveals a typical pattern of enhancement. A dense T2-weighted image on MRI is a sensitive (although not specific) finding. Radiolabeled red blood cell scans can also diagnose hemangiomas. Angiography would likewise be diagnostic but is not necessary. These lesions are usually asymptomatic and can simply be observed. They do not have a high risk for spontaneous rupture. Percutaneous biopsy is contraindicated because of the risk for bleeding. Resection by enucleation is appropriate for symptomatic lesions, for enlarging lesions, or if the diagnosis is uncertain. There is no established role for such treatments as arterial ligation, embolization, or radiation therapy.
Answer
B
24 Hepatocellular carcinoma is epidemiologically associated with all of the following except:
A Hepatitis A virus (HAV) infection
B Hepatitis B virus (HBV) infection
C Hepatitis C virus (HCV) infection
D Wilson disease
E Alcoholic cirrhosis
Ref.: 1, 3
Comments
Primary hepatocellular cancer, although less common in North America, is the most common malignant neoplasm worldwide. Endemic areas include sub-Saharan Africa, Southeast Asia, and Japan. The primary risk factors are chronic liver disease with cirrhosis (from essentially any cause), chronic infection with HBV or HCV, and various hepatotoxins. Hepatocellular carcinoma can develop in patients with liver disease related to alcohol abuse, hemochromatosis, α1-antitrypsin deficiency, Wilson disease, HA, and other conditions. Exogenous risk factors include dietary aflatoxins (found in grains, dairy products, and peanuts), oral contraceptives, anabolic steroids, vinyl chloride, and certain pesticides. HAV is not associated with hepatocellular cancer.
Answer
A
25 Which of the following statements is true regarding intrahepatic cholangiocarcinoma?
A Survival following resection is generally lower than that for distal bile duct cancer.
B Resection is contraindicated unless histologically negative margins can be obtained.
C The best survival is achieved with liver transplantation.
D Adjuvant chemotherapy improves survival following resection.
E None of the above
Ref.: 1, 7, 8
Comments
Cholangiocarcinoma arises from the bile duct epithelium and can occur anywhere along the biliary tract. It constitutes 5% to 20% of primary liver cancers. Tumors arising from the extrahepatic bile ducts differ from those located intrahepatically in terms of their clinical findings, therapy, and prognosis. Tumors of the extrahepatic bile ducts are typically manifested as biliary obstruction. Intrahepatic tumors appear similar to hepatocellular cancer, a liver mass with absent or vague symptoms such as pain, weight loss, nausea, and anorexia. The treatment of choice is surgical excision, which is associated with a 15% to 20% 5-year survival rate. The prognosis is best for tumors of the distal bile ducts that can be resected by pancreaticoduodenectomy. Tumors involving the bifurcation of the bile duct (Klatskin tumor) are less often resectable. Tumor size and the presence of satellite nodules are correlated with outcome. Histologically negative margins are always desirable, but prolonged survival can be attained even with microscopically involved margins. If the tumor cannot be resected, improved survival has been noted with bypass or stenting procedures. Liver transplantation for cholangiocarcinoma has been associated with frequent recurrence and has not generally been encouraging. Adjuvant chemotherapy has not typically been useful for bile duct cancer.
Answer
A
26 A 60-year-old African-American man with a history of right hemicolectomy for colon cancer comes to the office for routine follow-up. His laboratory work-up is significant for a carcinoembryonic antigen level of 80 ng/mL. CT of the chest/abdomen/pelvis shows an isolated hepatic lesion in the right lobe of the liver suspicious for metastasis. Which of the following is the best management option?
A Chemotherapy alone
B Chemotherapy and radiation therapy
C Colonoscopy and hepatic resection
D Hepatic resection
E Chemoembolization
Ref.: 1, 3, 7
Comments
Surgical resection remains the “gold standard” for select patients with hepatic metastases from colorectal cancer. Systemic chemotherapy alone is ineffective, with a 1-year survival rate of approximately 20% to 30%, whereas surgical resection has a cure rate of approximately 20% in appropriately selected patients. Over the last 2 decades, improvements in intraoperative techniques have afforded improved outcomes in liver surgery. Experienced centers demonstrate 5-year survival rates of 25% to 40% with mortality rates of less than 5%. Careful preoperative patient selection is paramount. Inadequate liver reserve, the presence of extrahepatic metastases (except limited pulmonary metastases or colonic anastomotic recurrence), total hepatic involvement, advanced cirrhosis, and vena cava or portal vein invasion are generally considered contraindications to curative resection. The goal is to resect all hepatic disease. Survival is adversely affected by margins that are positive for cancer or are less than 1 cm. As long as the resection margin is adequate, the specific type of liver resection (anatomic versus “wedge”) does not influence survival. Synchronous lesions discovered at the initial operation for colorectal cancer may be removed at the original operation if the length of the original procedure, general condition of the patient, extent of hepatic resection, and experience of the surgeon allow such resection. Otherwise, resection can be performed at a later date. This patient should undergo surveillance colonoscopy to evaluate for local recurrence, as well as resection of the isolated metastatic lesion.
Hepatic arterial infusion of chemotherapeutic agents has a higher response rate than does systemic administration, although adjuvant chemotherapy has not prolonged survival following hepatic resection in randomized studies. Radiation therapy is not useful for hepatic metastases. Ablative therapies, such as radiofrequency hyperthermia, may be useful for patients who cannot undergo resection.
Answer
C
27 Which of the following is the most accurate method for identifying hepatic metastases?
A Transabdominal ultrasound
B CT
C Laparoscopy
D Intraoperative palpation
E Intraoperative ultrasound imaging
Ref.: 4
Comments
Transabdominal ultrasound is as accurate as CT for detecting liver tumors that are 2 cm in size or larger. For smaller lesions, computed tomography is more accurate, although it can miss the smallest lesions (<1 cm). Laparoscopy is useful for identifying small metastases on the liver or peritoneal surfaces that escape discovery by noninvasive preoperative imaging modalities. Laparoscopy has been incorporated into the staging work-up of a variety of intra-abdominal malignancies, including those of the liver. However, one of its limitations is its ability to assess the interior structure of solid organs. It is now well recognized that intraoperative ultrasound is the most accurate method for detecting and assessing hepatic tumors. Not only does intraoperative ultrasound discover more lesions than any other modality (including palpation), but it also clearly demonstrates the anatomic relationship of tumors to important vascular structures, which is a critical determinant of resectability and the extent of resection necessary. Intraoperative ultrasound can be performed with handheld or laparoscopic transducers. Experience with intraoperative ultrasound for liver tumors has shown that the sonographic findings affect the surgical management of one third to one half of patients. Intraoperative ultrasound imaging has become an indispensable component of hepatic surgery.
Answer
E
28 A 56-year-old woman with cirrhosis of the liver secondary to alcohol abuse has had worsening mental status that has now progressed to hepatic coma. Which of the following can be used for initial treatment of a patient in hepatic coma?
A Reduction of dietary protein to 50 g/day or less
B Control of active bleeding
C Lactulose
D Neomycin
E All of the above
Ref.: 1-3
Comments
Treatment of hepatic encephalopathy and coma is aimed at limiting the nitrogen that the liver must metabolize by eliminating nitrogenous material from the gastrointestinal tract and by inhibiting its absorption. At the same time, precipitating causes are sought and treated. Nutritional support is important and can be initiated with standard amino acids and restriction of dietary protein. Cessation of any gastrointestinal bleeding from varices is an important step in reducing the conversion of intraluminal blood to ammonia. Lactulose acts as a cathartic and also inhibits the absorption of ammonia by acidifying the colon. Nonabsorbable antibiotics, such as neomycin and kanamycin, reduce colonic flora and the production of ammonia. Systemic antibiotics may be useful for treating specific infections that precipitate encephalopathy but are not indicated empirically. Because the colon is the major site of ammonia absorption, colon resection or exclusion has been suggested to improve encephalopathy but is not a widely used therapeutic measure.
Answer
E
29 A 43-year-old man with alcoholic cirrhosis has had increasing abdominal distention over the last month. His vital signs are stable and he is afebrile. Physical examination reveals a distended abdomen with a fluid wave. The initial management of the patient’s ascites should include all of the following except:
A Transjugular intrahepatic portocaval shunt (TIPS)
B Sodium restriction
C Diuretic administration
D Fluid restriction
E Diagnostic paracentesis
Ref.: 9
Comments
Ascites is the most common major complication of hepatic cirrhosis. It is associated with a 2-year survival rate of 50%, and its onset in a cirrhotic patient should prompt an evaluation for liver transplantation. Treatment of ascites depends on its cause, and therefore diagnostic paracentesis is required after a history and physical examination. Abdominal ultrasound can confirm the presence of ascites if it is not certain by examination. The serum-ascites albumin gradient is useful diagnostically. A high gradient (1.1 g/dL) indicates portal hypertension and suggests that the patient will be responsive to medical management consisting of sodium restriction (2000 mg/day) and oral diuretics. Usually, both spironolactone and furosemide are administered to produce fluid loss and natriuresis. Spironolactone alone may cause hyperkalemia, and furosemide alone is less effective. Medical therapy controls ascites in about 90% of patients. When the ascites is refractory, serial therapeutic paracenteses (with or without the administration of albumin or other plasma volume expanders) is indicated. Liver transplantation is the ultimate treatment. A peritoneovenous shunt is an option for patients with refractory ascites who are not transplantation candidates or who cannot undergo repeated paracenteses. These shunts are fraught with potential complications, however, and do not prolong survival in comparison with medical management. Transjugular intrahepatic portosystemic shunts or operative side-to-side–type portosystemic shunts may control the ascites in select patients.
Answer
A
30 Which of the following is an indication for TIPS?
A Recurrent variceal bleeding
B Ascites
C Spontaneous bacterial peritonitis (SBP)
D Hepatorenal syndrome
E Portal gastropathy
Ref.: 1, 3
Comments
Portal hypertension is responsible for the majority of the morbidity and mortality associated with cirrhosis, such as variceal bleeding, refractory ascites, and hepatic hydrothorax. First-line therapy for patients with primary variceal bleeding is endoscopic therapy with variceal band ligation or sclerotherapy. However, there is a high risk for rebleeding not amenable to endoscopic techniques (refractory bleeding) or continuation of bleeding (recurrent bleeding). The transjugular intrahepatic portosystematic shunt procedure decompresses the portal system by creating a portosystemic shunt and has been effective in up to 90% of patients. The primary treatment of ascites is medical management, although in patients with refractory ascites that is unresponsive to sodium restriction, high-dose diuretics, and other medical therapies, TIPS does improve their ascites. However, there is no survival benefit in this population. Hepatorenal syndrome, SBP, and portal gastropathy are not indications for a TIPS procedure.
Answer
A
31 Which of the following statements is true regarding SBP?
A The diagnosis can be made clinically without paracentesis.
B Infection is most commonly polymicrobial.
C Antibiotic therapy is reserved for patients with positive findings on ascitic fluid culture.
D Gram-negative enteric bacteria are often present.
E None of the above
Ref.: 3, 9
Comments
Spontaneous bacterial peritonitis is a potentially lethal complication of ascites that affects about 10% of patients with cirrhotic ascites. Fever and abdominal pain are common manifestations, but the signs and symptoms may be subtle. Diagnosis requires paracentesis with demonstration of an elevated ascitic fluid polymorphonuclear neutrophil (PMN) count (>250 cells/mm3) or, eventually, positive findings on culture. Antibiotic therapy should be instituted promptly based on an elevated ascitic fluid PMN count or on symptoms even if the PMN count is lower. Infection is usually from one organism, most commonly E. coli, Klebsiella, or pneumococcus. A third-generation cephalosporin is typically the preferred antibiotic. Differentiation from bacterial peritonitis secondary to a surgical condition is critical. Patients with SBP typically respond to appropriate antibiotics within 48 hours, and ascitic PMN counts decrease. Failure to improve, the presence of polymicrobial infection, or ascitic fluid with a total protein level greater than 1 g/dL, an LDH level greater than the serum level, or a glucose level less than 50 mg/dL suggests secondary peritonitis. Risk factors for SBP include previous SBP, variceal hemorrhage, and low-protein ascites (<1.0 g/dL). Short- or long-term prophylactic antibiotics may be appropriate for high-risk patients.
Answer
D
32 With regard to hernias in patients with ascites, which of the following statements is true?
A Increased abdominal pressure is one cause of umbilical hernias in patients with ascites.
B Umbilical hernia recurrence rates for patients with and without ascites are the same.
C Patients with asymptomatic groin hernias should be treated surgically.
D Preoperative paracentesis is not a helpful strategy for electively repairing these hernias.
E All of the above.
Ref.: 10
Comments
Umbilical and, less frequently, inguinal hernias occur in approximately 20% of patients with ascites. They develop as a result of increased intra-abdominal pressure, muscle wasting, fascial thinning, and nutritional deficits. The recurrence rate following repair of umbilical hernias in patients with ascites may be as high as 73%. Because of the high complication rate following hernia repair, it should not be entertained for asymptomatic hernias. Preoperative optimization with paracentesis helps decrease intraabdominal pressure. Ascites leakage following a surgical procedure should be treated aggressively, and early wound exploration with repair of fascial dehiscence is necessary. Diuretic therapy alone is ineffective in this situation.
Answer
A
33 Which of the following is a contraindication to radiofrequency ablation (RFA) of liver tumors?
A Proximity of the tumor to major vascular structures
B Multiple lesions
C In conjunction with liver resection
D Metastatic colon cancer
E None of the above
Ref.: 11, 12
Comments
Radiofrequency ablation is a technique in which a needle electrode is inserted into a malignant liver tumor. A radiofrequency generator is connected to the electrode, which produces localized tumor destruction with coagulative necrosis as the temperature of the tissue exceeds 50° C. Introduction of the electrode can be performed through a laparotomy incision, laparoscopically, or even percutaneously with the use of ultrasound guidance. This method has been used in patients with hepatocellular carcinoma, as well as in those with metastatic colon and rectal cancers. Some institutions combine the treatment with resection when multiple lesions are involved and resection alone would not leave enough viable hepatic parenchyma for survival. RFA works well when lesions are close to major vascular structures. The maximum size of lesion that can be ablated by RFA is unclear because multiple applications can be used, but it does appear to be more effective on smaller lesions (<5 to 6 cm).
Answer
E
34 Eight weeks after open heart surgery with transfusions, a 56-year-old man notes dark urine, fatigue, and anorexia. Physical examination discloses only mild, tender hepatomegaly. Laboratory investigations reveal a bilirubin level of 2 mg/dL; an AST level of 540 IU/L; an ALT level of 620 IU/L; an alkaline phosphatase level of 1120 IU/L; and negative assay results for hepatitis B surface antigen (HBsAg), hepatitis B core antibody (anti-HBc), immunoglobulin M anti-HAV antibody (IgM anti-HAV), and anti-HCV antibody (anti-HCV). Which of the following is the most likely explanation for the patient’s clinical condition?
A Acute viral hepatitis A
B Acute viral hepatitis B
C Acute viral hepatitis C
D Acute viral hepatitis D
E Acute viral hepatitis E
Ref.: 1, 3
Comments
Post-transfusion non-A, non-B hepatitis is mostly the result of HCV infection. The incubation period is usually 5 to 10 weeks, and the mean peak aminotransferase levels are 500 to 1000 IU/L. Anti-HCV antibody is commonly not detectable until 18 weeks after onset of the illness. Approximately 70% of patients with acute hepatitis C progress to chronic hepatitis and potentially cirrhosis. The negative serologic study results exclude acute infection with HAV and HBV. Hepatitis D (delta) virus (HDV) is capable of infecting only patients who also have HBsAg because HDV is an incomplete RNA virus. Hepatitis E (epidemic) virus is rare, except in association with water-borne epidemics in India, the Middle East, and South America.
Answer
C
35 Which of the following clinical conditions is indicated by the presence of serum antibodies against hepatitis B surface antigen (anti-HBs) and anti-HBc in the absence of HBsAg?
A Active, acute infection with HBV
B Normal response to vaccination with the hepatitis B vaccine
C Chronic active hepatitis secondary to HBV
D Recovery with subsequent immunity following acute hepatitis B
E Asymptomatic chronic carrier of HBV
Ref.: 1, 3
Comments
The pattern of negative HBsAg, positive anti-HBs, and positive anti-HBc assays is seen during the recovery phase following acute hepatitis B and clearance of HBsAg from the liver. This antibody pattern may persist for years and is not associated with liver disease or infectivity. Vaccination with the hepatitis B vaccine (genetically manufactured HBsAg particles without HBcAg or HBV DNA) is associated with the development of anti-HBs antibody alone. Active, ongoing infection with HBV, whether acute hepatitis, chronic active hepatitis, or an asymptomatic chronic carrier state, is manifested by the presence of HBsAg and anti-HBc in serum.
Answer
D
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