Epidermoid cyst mimicry: report of seven cases and review of the literature.

Cysts are entities encountered frequently in dermatological clinics. Various types of cysts have been described and include trichilemmal cysts, epidermoid cysts, steatocystomas, and the myriad of developmental cysts (branchial cleft cyst, thyroglossal duct cysts, bronchogenic cysts). Moreover, not all lesions that appear clinically as cystic structures are, in fact, cysts. Increased awareness of these mimickers and a systematic approach to the evaluation of these cases is essential. The authors report seven cases, over the course of six years, presenting to their dermatology department, all of which were originally clinically diagnosed as "cysts" and referred to the authors for management. In this article, the authors review seven cyst mimickers and describe important aspects of these diagnoses to increase awareness of the importance of a preoperative biopsy and evaluation. It is important to have a thorough understanding of the wide differential diagnosis of cutaneous nodules and to consider other causes of lesions that appear to be cysts, particularly in the anatomical locations described.