Stimulation of folliculo‐sebaceous proliferations by neurofibromas: a report of two cases

Two unrelated patients, a woman aged 44 and a man aged 56, with a type I neurofibromatosis, showed comedo-like formations at the top of some neurofibromas. One of them was excised in each case and they were studied histopathologically. The comedo-like formation of the first case mimicked the epithelial component of a fibrofolliculoma, and that of the second case had the structure of a primary late microcomedo and showed also anagen hair differentiation in the form of a follicular bulb and papilla. Both events are considered to be the result of a stimulation phenomenon and to reflect the essential role of the stroma in many cutaneous epithelial hyperplasias, hamartomas and possibly in some neoplasms.