Epidermal or sebaceous cysts are frequently encountered in clinical practice, and the slowly enlarging lesions are commonly appear on the trunk, neck, face, scrotum, and behind the ears. The term epidermal cyst is preferred over the historically used term sebaceous cyst. The cysts usually arise from ruptured pilosebaceous follicles or the lubricating glands associated with hairs or other skin adnexal structures. Within the cyst is a yellow, cheeselike substance commonly (but incorrectly) referred to as sebum. The rancid odor associated with some cysts reflects the lipid content of the cyst material and any decomposition of cyst contents by bacteria.
Clinically, the cysts can vary in size from a few millimeters to 5 cm in diameter. Cysts generally have a doughy or firm consistency; stony hard lesions suggest the possibility of alternate diagnoses. The cysts usually are mobile within the skin, unless the cysts have surrounding scar and fibrous tissue after a prior episode of inflammation.
The cyst contents induce a tremendous inflammatory response from the body after leaking from cysts. Epidermal cysts can have a tremendous amount of associated pus when inflamed, but culturing these inflammatory cells often reveals a sterile inflammatory response. Because of the discomfort, redness, and swelling associated with an inflamed cyst, many individuals prefer to have cysts removed before they have the opportunity to leak and become inflamed.
Inflamed cysts usually require incision and drainage of the pus and sebaceous material, with removal of the cyst wall at a later date. Attempts at definitive surgical care of actively inflamed cysts are often unsuccessful. Inflamed tissues bleed extensively and are unable to hold sutures for proper closure.
After the inflammation resolves, standard incision and removal techniques historically have been employed to remove the entire cyst. Cyst recurrences are prevented by complete removal of the cyst wall. Unfortunately, previous excision techniques produced large skin defects and scars in removing the entire lesion intact. The minimal excisional technique was developed to remove the cyst walls with a minimal skin scar.
Most cysts are simple, solitary lesions. However, some clinical situations warrant added care. Multiple epidermal cysts that are associated with osteomas and multiple skin lipomas or fibromas may represent Gardner's syndrome. Gardner's syndrome is associated with premalignant colonic and gastric polyps. Dermal
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cysts of the nose, head, and neck often appear similar to epidermal cysts. However, a dermal cyst can have a thin stalk that connects directly to the subdermal space, and surgery can produce central nervous system infection. Multiple cysts, such as in the fold behind the ear, can be treated alternately with medical therapy (i.e., isotretinoin). When a cyst is removed with any technique, the medical provider should palpate the surgical site to ensure that no tissue or lesions remain. Rarely, the clinician may encounter basal cell carcinoma or squamous cell carcinoma associated with epidermal cysts, and histologic examination of cyst walls is recommended whenever unusual or unexpected clinical findings are encountered.
INDICATIONS
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PROCEDURE
Anesthesia is accomplished with a two-step procedure. Begin by placing a small (30-gauge, ½-inch long) needle into the skin overlying the cyst. Place the needle tip in an intradermal location, preferably near the plugged pore (i.e., comedone) that may be visible overlying the cyst (Figure 1A). When the needle tip is correctly placed, there is resistance to injecting the anesthetic within the skin, and a bleb develops in the skin. In the second step, place a longer (25-gauge, 1-inch long) needle on the syringe. Insert the needle laterally, angling the needle 45 degrees down to below (behind) the cyst (Figure 1B). Place an adequate amount of anesthetic (usually 3 to 6 mL) beneath the cyst, thereby fully anesthetizing the posterior wall of the cyst.
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(1) Anesthetize the skin overlying the cyst and the posterior wall. Avoid placing needle tip into the cyst, because the anesthetic increases the pressure and causes the cyst to explode. |
PITFALL: If the needle tip is placed inadvertently within the cyst, the anesthetic will increase pressure and cause the cyst to explode, often shooting the sebaceous material across the room.
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Create an entry into the cyst by vertically stabbing a no. 11 (sharp-pointed) scalpel blade into the cyst. Usually, a single up-and-down motion is sufficient to create the passage into the cyst. Sometimes, the cyst can be squeezed from the sides, and sebaceous material immediately comes up. However, the opening can be gently stretched with insertion of a straight hemostat down into the cyst.
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(2) Create an entry into the cyst by vertically stabbing a no. 11 scalpel into the cyst. |
PITFALL: Many operators fail to enter the cyst with the scalpel blade. By directing the blade toward the center of the cyst and inserting until a “give” is felt as the blade tip enters the cyst, the pass of the blade usually will be successful.
PITFALL: The clinician should not be positioned directly over the cyst. Opening a cyst that is under pressure can result in upward spraying of the cyst's contents. Hold some gauze in the nondominant hand to act as a shield when opening the cyst.
Alternately, some practitioners prefer the ease that is afforded by creating a larger opening. A 3- 4-mm biopsy punch can be inserted directly down into the cyst. The comedone or pore usually is included in the skin that is removed with the biopsy punch. This opening allows much easier emptying of the cyst, but it has the disadvantage of requiring suture closure after the procedure.
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(3) Alternatively, a 3- or 4-mm biopsy punch can be inserted directly down into the cyst. |
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The cyst contents must be emptied before attempting removal of the cyst wall. Using the thumbs to squeeze the cyst generally provides the greatest possible hand strength (Figure 4A). Place the thumbs on opposite sides of the cyst opening. Press straight down with the greatest possible force, and firmly rotate the thumbs toward each other and then up toward the opening (Figure 4B).
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(4) The cyst contents must be emptied before attempting removal of the cyst wall. |
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Squeezing out the cyst's contents can cause the sebaceous material to erupt into the face of the practitioner. A more controlled process involves placing a hemostat into the cyst's opening and squeezing the sebaceous material up into the open hemostat blades. Squeezing is accomplished using fingers on the nondominant hand. After the hemostat fills with material, it is withdrawn with the blades still open, and the sebaceous material is wiped away using gauze. The hemostat is reinserted and the process repeated.
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(5) A more controlled process of emptying the cysts contents involves placing a hemostat into the cyst opening and squeezing the sebaceous material up into the open hemostat blades. |
Use gauze to wipe away sebaceous material on the skin surface (Figure 6A). Continue vigorously squeezing until all material is removed. The “kneading” produced from the rocking motion of the thumbs toward the cyst opening helps to loosen the cyst from all surrounding subcutaneous and cutaneous attachments. Move the thumbs around the opening so that the vigorous massaging is performed on all sides of the cyst (Figure 6B).
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(6) Use gauze to wipe away sebaceous material on the skin surface, and continue squeezing vigorously until all material is removed. |
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After the entire site has been vigorously kneaded and the cyst is completely emptied, reach straight down through the opening using straight hemostats. Grasp the posterior wall of the cyst, and gently elevate toward the skin surface.
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(7) Using straight hemostats, reach straight down into the opening, grasp the posterior wall of the cyst, and gently elevate it toward the skin surface. |
If resistance is encountered, grasp the cyst wall with a second hemostat just below the initial hemostat application, coming from a horizontal plane. Continue to elevate with both hemostats. If more of the cyst wall slides through the skin opening, the first hemostat can be released and used to regrasp the cyst wall below the second hemostat.
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(8) If resistance is encountered, grasp the cyst wall with a second hemostat just below the initial hemostat application, coming from a horizontal plane. |
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An attempt is made to remove the entire cyst wall intact. If the cyst wall breaks, enter the skin opening and vigorously grasp in all directions until additional cyst wall is grasped and pulled out.
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(9) If the cyst wall breaks, enter the skin opening, and vigorously grasp in all directions until additional cyst wall is grasped and pulled out, because no part of the cyst wall can remain in the wound. |
PITFALL: If any cyst wall remains in the wound, the cyst will recur. It is critical that all of the cyst wall be removed. The operator should vigorously search all sides and the depth of the wound. It is critical that sufficient preprocedure anesthesia be administered to permit this vigorous tugging within the wound.
Occasionally, previous inflammation of the cyst causes scarring and tethering of the cyst wall to surrounding tissues. This usually prevents removal of the cyst wall by the minimal technique. If the operator is unable to remove the cyst wall using the minimal technique, the operator should make a fusiform excision surrounding the skin opening (Figure 10A) and cut down into the subcutaneous tissues with a no. 15 blade to allow removal of the entire cyst wall (Figure 10B). The site is then closed with sutures (see Chapter 12).
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(10) If it is not possible to remove the cyst wall using the minimal technique, make a fusiform excision surrounding the skin opening, and cut down into the subcutaneous tissues with a no.15 blade to allow removal of the entire cyst wall. |
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CODING INFORMATION
Use the benign excision codes (11400–11446) for removal of these lesions. The code selected is determined by size and location of the lesion. The codes include local anesthesia and simple (one-layer) closure, although the codes can be used if the minimal incision technique is used and no suturing is required. The sites for these codes include the following: trunk, arms, or legs (TAL); scalp, neck, hands, feet, or genitalia (SNHFG); and face, ears, eyelids, nose, lips, or mucous membrane (FEENLMM).
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INSTRUMENT AND MATERIALS ORDERING
The basic office surgery instruments are used for the standard excision technique (see Appendix A.) The minimal sebaceous cyst removal technique can be performed with a no. 11 scalpel blade, two or three small mosquito hemostats, and 1 inch of sterile gauze. A suggested anesthesia tray that can be used for this procedure is listed in Appendix G. Skin preparation recommendations appear in Appendix H.
BIBLIOGRAPHY
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