Introduction
CHAPTER 50 Cysts
Rebecca J. Larson Amy J. Schutte Sandra Lee
SUMMARY
Cysts are a frequent patient complaint, and removal may be motivated by
tenderness, functional compromise, or aesthetic concern.
Most cysts respond well to excisional approaches, ranging from small punch
excisions to large elliptical approaches.
Beginner Tips
Never attempt to excise an actively infected cyst; instead, consider I&D or a course of
antibiotic therapy prior to attempting aggressive surgical intervention.
Cysts that have been previously treated, infected, or manipulated will be more
recalcitrant to treatment and may require sharp dissection or full excision.
Expert Tips
With experience, cysts may be delicately dissected en bloc from a small incision site.
Dead space minimization is vital for postoperative success, and may be accomplished
via fascial plication sutures or percutaneous suture placement.
Don’t Forget!
Though minimal access incisions may be tempting, this must be weighed against the
undesirable smell associated with cyst rupture which may be disturbing to the patient.
Careful removal of all cyst contents and the entirety of the cyst wall will help mitigate
the risk of recurrence or postoperative complications.
Pitfalls and Cautions
Even expert diagnosticians may be fooled by cyst mimickers; therefore, all suspect
cystic nodules should be removed, and every cyst should be sent for histopathology.
Excising large cysts overlying nerve danger zones may entail a risk of permanent nerve
damage; this should be explained to patients as part of the informed consent process.
Patient Education Points
Patients should always be told that they are trading the cyst for a scar; if they are at all
hesitant, defer the procedure.
Even with complete excision, cysts may recur; patients should be warned that this is a
possibility before starting surgery.
Billing Pearls
Depending on clinical practice, most excised cysts are removed for symptomatic
reasons, and are therefore billed with a benign series excision code (11400 series) coupled with a repair code (12000 and 13000 series).
Be sure to document the rationale for the medical necessity of cyst excision if it is to
be billed to insurance.
Cysts removed purely for cosmetic reasons should not be billed to insurance.
CHAPTER 50 Cysts
INTRODUCTION
Cysts are frequently encountered in dermatologic surgery, and patients may present with a growing, irritated, or infected cystic nodule. While patients often present due to symptomatic concerns, they occasionally seek treatment for primarily aesthetic reasons. Most epidermal inclusion and pilar cysts can be identified clinically by their appearance and anatomic location, though excised cystic nodules should always be evaluated histopathologically, as other skin and soft-tissue tumors—everything from lipomas to Merkel cell carcinoma—can clinically mimic epidermal cysts.
EPIDEMIOLOGY
Many patients and nondermatologists refer to epidermal inclusion and pilar cysts colloquially as sebaceous cysts. This terminology should probably be avoided, as the only truly sebaceous cyst is a steatocystoma, which is encountered only infrequently, and is sometimes associated with pachyonychia congenita type 2 and steatocystoma multiplex.1,2 Epidermal cysts are synonymous with infundibular cysts or epidermal inclusion cysts, as they are all derived from the follicular infundibulum. These are sometimes divided into primary and secondary lesions, caused by follicular disruption or traumatic transformation, respectively.
Epidermal cysts are the most common type of cyst, and frequently occur on the face or upper trunk.3 When epidermal cysts occur on the scalp, they are sometimes clinically confused with pilar or trichilemmal cysts. Pilar (trichilemmal) cysts differ histologically from epidermal cysts, and occur almost exclusively on the scalp.3 Milia, smaller variants of epidermal cysts, arise most frequently on the face in adults, though they may also be induced by secondary phenomena such as blistering, trauma, topical corticosteroid atrophy, laser resurfacing, and deep chemical peels.4,5
Surgical excision is the mainstay of treatment for epidermal and pilar cysts, though other surgical modalities may be explored as well. When multiple cysts are present,
underlying syndromes, such as basal cell nevus syndrome and Gardner syndrome,6,7 may be considered. Multiple milia can be found in the setting of oral–facial–digital syndrome, hereditary hypotrichosis, Rombo, and Bazex syndromes.5 Therefore, a complete history and physical examination are encouraged.