We report a case of Becker's nevus with smooth muscle harmatoma in a 24-year-old man, who showed localized excessive-hairy, dark brown colored patch including pin-head sized follicular papules on the left side of bucca, mandible and neck. Histologic examination revealed hyperpigmentation of the basal layer of epidermis and hyperplasia of smooth muscle bundles in the dermis.

Reactive perforating collagenosis is a unique cutaneous disorder characterized clinically by recurrent, umbilicated, crusted papules arising in response to minor trauma. This disorder belongs to a group of dermatologic conditions that have been classified as "transepidermal elimination" syndrome.

We report a patient with acquired reactive perforating collagenosis without any associated disease and family history.