A case of melanocytic nevus combined with a vellus hair cyst

The combination of melanocytic nevus with other tumors of epidermal or adnexal origin has been described since the first case reported by Andresen and Enos in 1952. Most of reported cases are melanocytic nevi combined with common epidermoid cysts. The combination of nevus and cyst could possibly be misdiagnosed clinically as a malignant melanoma upon initial examination. A 58-year-old woman presented with an asymptomatic, solitary, skin-colored, erythematous 1.0 cm-diameter pedunculated nodule on the occipital scalp which had been present childhood. The histopathologic specimen of the nodule showed a solitary cyst surrounded by intradermal melanocytic nevus. The cyst was located in the dermis lined by squamous epithelium, which was ruptured and inflamed. It contained degenerated keratin materials and multiple transversely and obliquely cut vellus hairs. We herein report a rare case of melanocytic nevus combined with a vellus hair cyst.