Clinical features

•Common, generally solitary, asymptomatic, keratin plugged, comedone-like cystic invagination

•Few mm to 1 cm or more

•Face & neck

•Exceptionally on trunk

•2M:1F

•Generally, middle-aged or elderly

Histological findings

•A keratin-plugged, dilated  follicular infundibulum lined by squamous epithelium and showing epithelial strands and/or buds emanating from ”cyst” wall

•The epithelium is often acanthotic showing hyperkeratosis & parakeratosis

•Exceptionally, vellus hair &/or sebaceous glands (overlapping trichofolliculoma)

•Some authors regard it as a true ”tumor” of the infundibulum (infundibuloma)