Folliculosebaceous cystic hamartoma with hair shaft fragments.

A 57-year-old Japanese male presented with a folliculosebaceous cystic hamartoma (FCH) on his left ear, characterized by a dome-shaped nodule containing hair shaft fragments within a cystic structure. Histological analysis showed a large cyst surrounded by sebaceous lobules and rudimentary hair follicles, with laminated orthokeratotic keratin and hair shaft fragments inside. The fibrous stroma invaded the sebaceous lobules, and clefts were observed around the folliculosebaceous units. This case was noted for the unusual presence of hair shaft fragments in the cyst, and the study included a review of similar cases in the literature.