Trichoblastoma

Trichoblastomas are a skin condition characterized by benign neoplasms of the follicular germinative cells known as trichoblasts.
Trichoblastic fibroma is a term used to describe small nodular trichoblastomas that contain a conspicuous fibrocytic component, sometimes constituting over 50% of the lesion.
Image at left shows a trichoblastoma from a 68-year-old Caucasian male. It shows a pseudo-encapsulated, multinodular, basaloid tumor with fibrocellular stroma spanning the reticular dermis extending into subcutaneous fat. No epidermal connection or retraction artifact was noted. Tumor lobules were arranged as monomorphous basaloid cells in a cribriform pattern with peripheral palisading some resembling abortive hair follicles. Focally, tumor lobules exhibited squamous eddies, papillary mesenchymal bodies, and a germinative component comprising basaloid cells admixed with distinct pales cells .