ABSTRACT

While trichoblastoma is a rare tumor with hair follicles differentiation, it is the most frequent benign tumor developing on nevus sebaceous.

It generally appears as a solitary asymptomatic skin-coloured papule or nodule on the scalp and neck. It should be differentiated clinically and histopathologically from basal cell carcinoma. There are various histopathologic subtypes of this adnexal tumour and pigmented trichoblastoma is one of the rarest forms.

A young adult female patient presented with a pigmented smooth-surfaced nodule on the scalp, which had enlarged within four years without a preexisting lesion. The histopathological diagnosis was pigmented trichoblastoma. Trichoblastoma may also present without a preexisting nevus sebaceous and may sometimes be of the pigmented type. (Turk J Dermatol 2011; 5: 107-9)