Nevus with cyst. A report of 93 cases.

Nevus with cyst is characterized by a melanocytic nevus that is closely associated anatomically with an epidermoid cyst. We describe the clinicopathologic manifestations of 93 cases (from 92 individuals) observed during a 6-year period and review the features of the 69 previously reported nevi with cysts in the world literature. It is important for both clinicians and pathologists to recognize this common benign condition because growth of these lesions is frequently misinterpreted by the patient as representing either a new melanoma or malignant transformation of a preexisting lesion. Variants of nevus with cyst include lesions in which the nevus is a congenital, "dysplastic," blue, or Spitz nevus. The cysts may be steatocystomas, hidrocystomas, dermoid, or trichilemmal cysts. In some cases, folliculitis may be present within the nevus instead of a true cyst.