Clinical and histologic features of 64 cases of steatocystoma multiplex.

Steatocystoma multiplex (SM) shares many clinical features and may show overlapping histopathological features with eruptive vellus hair cyst (EVHC). Clinical data and pathologic features of 64 patients with SM were evaluated in detail. Most of the cases were sporadic, with an average onset age of 26 years and distribution on the arms, chest, axillae, and neck. All cases exhibited eosinophilic cuticle and lack of granular layer, and 17-42% displayed vellus hair, hair follicles, keratin, and smooth muscle components within the cavity, in the wall, or adjacent to it. The results of this study add further evidence to the hypothesis that SM is a hamartomatous condition and that SM and EVHC are variants of one disorder which originates in the pilosebaceous duct.