A 5-year-old boy with comedo-like lesions on the right buttock.

A healthy, 5-year-old boy presented with cutaneous lesions on the right buttock, evident at birth. A physical examination revealed plugged pores in a linear distribution with the appearance of comedones and scar areas. Histopathological exam revealed multiple atrophic cystically dilated hair follicles containing abundant keratinous debris and small projections of epithelial cells extending from the wall of the cyst into the surrounding dermis, compatible with nevus comedonicus.