Shawn J. Pelletier
Presentation
A 38-year-old woman with a history of a thyroid nodule and use of an ethinyl estradiol and etonogestrel vaginal ring presents with epigastric pain and early satiety. She states her pain has been present for months but now has increased in severity and limits her quality of life. On physical exam, she is noted to have epigastric fullness and mild epigastric tenderness. An ultrasound of her liver demonstrates an incidental 15-cm mass in the left lateral segment of her liver.
Differential Diagnosis
The potential differential diagnoses are listed in Table 1. Most incidental liver masses identified in an otherwise healthy individual are benign, but the possibility of a malignant etiology needs to be investigated. While most metastatic liver masses come from a colorectal origin, neuroendocrine tumors and other cancers are possible. In addition, primary liver cancers should be considered including hepatocellular carcinoma (HCC), cholangiocarcinoma, and gallbladder cancer.
TABLE 1. Differential Diagnosis of Incidental Liver Mass
The most likely etiology of the tumor described in this patient setting is one of several benign tumors. Cavernous hemangiomas are benign vascular lesions of unclear etiology. They are the most common benign liver tumor and can be found in all age groups. Hemangiomas >4 cm in diameter have been termed “giant hemangiomas.” Eleven to fourteen percent of cases may be symptomatic. Regardless of size, the risk of rupture and hemorrhage is minimal. In rare cases, large cavernous hemangiomas may lead to high cardiac output heart failure or Kasabach-Merritt syndrome.
Focal nodular hyperplasia (FNH) is the second most common benign lesion. In general, FNH is viewed as hyperplastic and not neoplastic. Recent studies demonstrate that these evolve from portal tract injury that leads to oxidative stress and activation of hepatic stellate cells forming a central scar. FNHs are typically found in women between the ages of 30 and 50 years. There is some association with the use of oral contraceptives, but it is felt that the use of oral contraceptives has a low likelihood to lead to progression.
Hepatocellular adenomas are typically found in women between 30 and 50 years and can enlarge particularly with the use of oral contraceptives or during pregnancy. Hepatic adenomas tend to have more heterogeneous imaging characteristics. In general, the management of adenomas is more aggressive than most other benign lesions because rupture and hemorrhage have been reported to occur between 11% and 29% of cases and the risk is greatest if the tumor is more than 5 cm in diameter. Malignant transformation into HCC has also been reported to occur in up to 5% to 10% of lesions. Liver adenomatosis can occur and has been previously defined as having more than 3 to 10 adenomas.
Workup
The algorithm for the evaluation of a patient with a liver mass is depicted in Figure 1. Laboratory evaluation includes a complete blood count, coagulation studies, hepatitis screen, liver function tests, and tumor markers (CEA, AFP, CA-19-9).
FIGURE 1 • Algorithm for evaluation of a liver mass.
Incidental solid and cystic lesions within the liver are being detected more commonly due to increased utilization of modern imaging. In otherwise healthy individuals, most incidental masses are benign. Radiologic characteristics and clinical features can often define the etiology of the liver mass, thus reducing the need for percutaneous biopsy. However, after adequate imaging has been performed, 10% of lesions that remain indeterminate may be malignant. Obtaining an accurate diagnosis is critical because management ranges from observation to surgical resection.
The patient undergoes further evaluation of this liver mass with a multiphasic liver MRI, which reveals a 15-cm mass arising from the left lateral segment of the liver, displacing the spleen and the stomach. In addition, four lesions, all <2 cm in size, are noted in the right lobe of her liver (Figure 2). These lesions have peripheral nodular enhancement during the arterial phase of the MRI and progressive centripetal enhancement during the venous phase. All lesions are consistent with cavernous hemangiomas.
FIGURE 2 • Dynamic contrast-enhanced MRI of a 38-year-old woman with a liver mass.
Diagnosis and Treatment
Once adequate imaging is obtained, if a diagnosis of FNH is made, the patient can be observed. If an FNH liver mass is symptomatic and no other cause for the symptoms can be identified, resection may be considered. For most hepatic adenomas, consideration should be given to the risk of resection compared to serial imaging. Adenomas with a diameter >5 cm have an increased risk of hemorrhage or malignant transformation. Therefore, resection is preferred if it can be performed safely.
If the diagnosis is uncertain after adequate imaging, consideration can be given to obtaining a percutaneous core liver biopsy. Biopsy should be performed only when the results will change management. In other words, if the lesion is symptomatic or has radiologic findings concerning for malignancy, proceeding with resection without biopsy is reasonable. In general, biopsies can be obtained safely in most clinical settings and have an approximate 1% risk of either bleeding or peritoneal seeding if the tumor is malignant. Also, because the histologic architecture is necessary for the diagnosis of many of these lesions, obtaining a fine needle aspiration is often unhelpful. If the diagnosis remains indeterminate after biopsy, resection should be performed.
Some authors have suggested that a laparoscopic approach to liver tumors is associated with an easier recovery and therefore may expand the indications for surgical resection. However, even with a laparoscopic approach, the risk of complications remains and many of these lesions have a low risk for developing malignant degeneration or bleeding. In addition, an operation performed for pain from a liver tumor may be associated with postoperative pain as well and patient selection for this indication is critical.
Overall, significant advances have been made with liver surgery so that mortality rates are often reported to be <2% and even as low as 0.2% in some populations. This is partly due to improvements in anesthesia and critical care as well as an increased understanding of intrahepatic anatomy. Preoperative and intraoperative imaging, including intraoperative liver ultrasound, allows for better preoperative planning and performing segmental resections. Performing portal vein embolization of the affected side may allow for hypertrophy of the future surgical remnant in highly selective cases. In addition, the development of “bloodless” liver surgery has improved outcomes using techniques such as intermittent inflow occlusion (Pringle maneuver), isohemodilution, total vascular isolation, maintenance of low central venous pressures, and improved dissection instruments (hydrojet dissection, ultrasonic dissection, saline-cooled coagulation, bipolar cautery, surgical stapling techniques, among others), argon beam coagulation, and fibrin sealants.
Surgical Approach
Laparoscopic Resection
To perform laparoscopic liver resection safely, the surgeon must have extensive experience with both open liver surgery and advanced laparoscopic techniques. In general, experience can be accumulated by starting with peripheral lesions within the left lateral segment or on the inferior aspect of the liver. As skills develop, resection of lesions within segments five and six can be attempted. Resection of tumors within segments seven and eight are more difficult but can be performed safely with appropriate experience. Ultimately, more than 75% of all patients with liver tumors can be approached with a laparoscopic technique, even including trisegmentectomy. As with any laparoscopic procedure, a surgeon should not hesitate to convert to an open procedure if there is inadequate exposure, hemorrhage, or concern for obtaining an adequate surgical margin.
While laparoscopic liver resections can be performed using a straight laparoscopic or hybrid approach, the hand-assisted approach offers many advantages. This allows for palpation and direct examination of the liver and abdominal cavity, adequate retraction of the relatively large liver, an improved ability to obtain a negative margin, and the ability to manually control hemorrhage. The patient is placed in the supine position and adequately secured to the table to allow for steep reverse Trendelenburg and rotation of the operative table. The hand-assist device is almost always placed in the midline near the umbilicus. For lesions in the superior aspect of the liver, the hand-assist device may be placed slightly higher on the abdomen. Positioning of the trochars depends on the location of the tumor for resection but attention should be paid to placing 12-mm trochars strategically so that laparoscopic staplers can be utilized. After the liver and the abdomen are visually inspected and palpated, ligamentous attachments are divided. An intraoperative liver ultrasound is performed, using either a T probe through the hand port or a laparoscopic ultrasound probe. Attention is first turned to a formal evaluation of the liver with particular attention paid to identifying lesions within the liver that were not identified on preoperative imaging. The known lesion is then evaluated and the vascular and biliary anatomy are noted. Margins for resection can be marked on the capsule of the liver using cautery. For lesions that are very close to major vascular or biliary structures and the lesion is known to be benign, consideration can be given to enucleating the tumor near these areas. If the tumor is concerning for malignancy, a margin should be obtained. Intermittent inflow occlusion can be utilized by placing a Penrose drain around the porta hepatis. The liver parenchyma is then divided using any of a number of different techniques, such as using ultrasonic dissection until major vascular structures are encountered. Small- to medium-sized vascular structures can be clipped and divided. Larger vascular structures and the portal plate are usually divided using an endovascular stapler. The tumor can then be removed via the hand port. Hemostasis on the cut edge of the liver can be obtained using the argon beam coagulation or standard cautery. The cut edge of the liver is also carefully inspected for potential bile leaks that can be oversewn. The use of a sealant agent can be considered to minimize postoperative biliary leaks. Placement of a drain near the cut edge of the liver may be considered for observation and potential treatment of a postoperative biliary leak (Table 2).
TABLE 2. Key Steps to Laparoscopic Liver Resection
Open Resection
In general, the technique used for open resection is similar to that of a laparoscopic resection. Placement of an epidural for postoperative pain management should be considered preoperatively. With the patient in the supine position, a right subcostal incision with upper midline extension is made. This allows adequate exposure to the left and right lobes of the liver as well as exposure to the suprahepatic vena cava and the lower abdomen if a Roux-en-Y hepaticojejunostomy needs to be constructed. Prior to placing a fixed retractor, the round and falciform ligament should be divided and any adhesions of the liver to the anterior abdominal wall should be mobilized to avoid tearing of the hepatic capsule leading to bleeding. As described in the laparoscopic approach, the abdomen and the liver are inspected, the lobe of the liver to be resected is mobilized, and an intraoperative liver ultrasound is performed. The liver resection itself is performed using similar techniques to divide the liver parenchyma. Inspection of the cut edge of the liver is also carefully performed to help avoid postoperative bile leaks. The abdomen is closed in the standard fashion, and a drain may be placed to diagnose and treat potential postoperative bile leaks (Table 3).
TABLE 3. Key Steps to an Open Liver Resection
Special Intraoperative Considerations
Several unexpected findings or complications may be encountered. The liver mass may ultimately be identified as a metastasis from another primary source. In this setting, biopsies to obtain an accurate diagnosis should be obtained and intraoperative staging should be performed. If appropriate, proceeding with resection of the liver tumor along with the primary tumor can be considered. This may be encountered in the setting of a colorectal malignancy or a neuroendocrine tumor. Additional hepatic lesions may also be identified that were not identified on preoperative imaging. If possible, consideration can be given to resection of these lesions as well. If there is concern for leaving an inadequate remnant, these lesions may also be treated using radiofrequency or microwave ablation.
During resection, preparation should always be made for unexpected hemorrhage. This includes preoperative communication with the anesthesia team to insure that adequate vascular access is present. Depending on the location of bleeding, control can often be obtained with manual compression or packing. A Pringle maneuver can also be used. In cases of extreme bleeding, total vascular isolation of the liver can be obtained by performing a Pringle maneuver as well as clamping the vena cava in a supra- and infra-hepatic position.
Postoperative Management
While most patients undergoing liver resection do not require treatment in an ICU, a low threshold for ICU care should be maintained if there is any concern for bleeding, hepatic insufficiency, need for observation of renal function, or other concerns based on the patient’s comorbidities. The patient’s volume status, hepatic, and renal function should be closely monitored and managed in the postoperative period. Pain can be controlled with either patient-controlled analgesia using intravenous opioids or an epidural. While an ileus may occur, this is usually limited if the majority of the surgical procedure occurred in the right upper abdomen; therefore, a postoperative nasogastric tube is usually unnecessary, and oral intake can be advanced relatively quickly. If bile is not present within the closed suction drain, the drain can be removed within several days postoperatively. If bile is present within the drain and is at a relatively low volume, the drain should be left in place and can be removed as an outpatient once the bile leak has resolved. If a high-volume leak is present, placement of an endobiliary stent to decompress the biliary tree may be necessary.
Case Conclusion
The patient undergoes successful laparoscopic resection of the largest left lobe liver mass using a hand-assisted technique (Figure 3) and is discharged from the hospital without complications on postoperative day 4. The final pathology returns confirming a giant cavernous hemangioma. Two years later, she remains pain free.
FIGURE 3 • Laparoscopic resection of a liver mass using a hand-assisted technique. A: Laparoscopic image of a 15-cm left lateral segment hepatic hemangioma. B: Transection of the liver parenchyma using an ultrasonic dissector. C: 15-cm hemangioma removed from a 7-cm laparoscopic hand port incision.
TAKE HOME POINTS
• Modern imaging has led to increased detection of incidental liver masses.
• In otherwise healthy individuals, most incidental masses are benign.
10% of indeterminant lesions may be malignant.
• Better definition of radiologic characteristics and clinical features has led to
Accurate radiologic diagnosis
Reduced need for biopsy
• Management ranges from observation to surgical resection.
SUGGESTED READINGS
Buell JF, Cherqui D, Geller DA, et al. The international position on laparoscopic liver surgery: the Louisville statement, 2008. Ann Surg. 2009;250:825–830.
Clavien PA, Petrowsky H, DeOliveira ML, et al. Strategies for safer liver surgery and partial liver transplantation. N Engl J Med. 2007;356:1545–1559.
Jarnagin WR, Gonen M, Fong Y, et al. Improvement in perioperative outcome after hepatic resection: analysis of 1,803 consecutive cases over the past decade. Ann Surg. 2002;236:397–406; discussion 406–407.
Koffron AJ, Auffenberg G, Kung R, et al. Evaluation of 300 minimally invasive liver resections at a single institution: less is more. Ann Surg. 2007;246:385–392; discussion 392–394.
Yoon SS, Charny CK, Fong Y, et al. Diagnosis, management, and outcomes of 115 patients with hepatic hemangioma. J Am Coll Surg. 2003;197:392–402.