Table 1 Histopathological differential diagnoses of nevus comedonicus
Nevus comedonicus | Trichofolliculoma | Dilated pore of Winer | Pilar sheath acanthoma | Folliculocystic and collagen comedo hamartoma | Hair cortex | |
|---|---|---|---|---|---|---|
Localization | ||||||
Head | + | + | + | |||
Face | + | + | + | + | ||
Neck | + | + | ||||
Trunk | (+) | + | + | + | ||
Limbs | + | |||||
Follicles | Numerous open follicles | Open ‘mother’ follicles | Open ‘mother’ follicles | Numerous open follicles | Solitary lesions | |
Cysts | + | + | + | |||
Hair shafts | − | +, vellus | − | − | ||
Lamellated keratin | − | − | − | − | − | |
Others | Massive epithelial proliferations without follicles | Abundant collagen formation | ||||