Eruptive Vellus Hair Cyst

Eruptive vellus hair cysts (EVHC) were described as asymptomatic papules, typically found on the chest but also on other body parts. The cause of EVHC was unknown, though it might have been linked to abnormal vellus hair follicle development, with a possible autosomal dominant inheritance pattern. The condition affected young to middle-aged individuals without gender preference. Treatments like oral vitamin A and keratolytic agents were ineffective, but spontaneous resolution could occur, possibly through transepithelial elimination or an intracutaneous foreign body reaction. Histologically, the cysts were located in the middermis, lined with squamous epithelium, and contained keratinous material and vellus hair shafts, with no inflammation unless the cyst wall was compromised.