Your diagnosis is: C. Epithelial inclusion cysts
Your treatment plan is: D. No treatment required
Epithelial inclusion cysts are common and most often require no intervention. They can occur spontaneously or after vulvar trauma, such as obstetrical lacerations or episiotomies where the epithelium becomes trapped. The cysts are lined by keratinizing stratified squamous epithelium. Keratinaceous debris can accumulate, which appears “cheesy” when extruded and can sometimes have a foul odor (Figure 2). Unless the cysts are bothersome or enlarging, no intervention is necessary. If they are bothersome, excision alone or with drainage can be performed. Most patients simply can be reassured that epithelial inclusion cysts are not concerning and quite common vulvar findings.
Another condition in the differential diagnosis in this case is molluscum contagiosum (Figure 3). Molluscum contagiosum is caused by a DNA Pox virus and typically has an umbilicated center. Mollusca often occur in children but they are also seen in sexually active adults. Lesions appear 2 to 6 weeks after exposure to the virus and range in size from pin-head to pencil eraser size, with an umbilicated center. Pruritus is a common complaint and scratching further disseminates the virus onto other parts of the skin. If the lesions are asymptomatic, they can be left alone and resolve without intervention. However, if molluscum contagiosum is symptomatic, it is responsive to removal with a dermal curette, topical application of cantharidin (“blister beetle juice”), imiquimod, trichloroacetic acid, or application of liquid nitrogen. Other options for topical therapy include iodine and salicylic acid, potassium hydroxide, and tretinoin. Oral cimetidine has been used as an alternative treatment in small children when there is concern about pain associated with cryotherapy, curettage, and laser therapy or to avoid the possibility of scarring.