Tricoadenoma of Nikolowski

Abstract

The patient, aged 50 years, with no relevant clinical history, complained of a symptomless, soft tumor of the right buttock that had been present for many years. On examination, it was found to be pediculate, oval, somewhat erythematous, firm on palpation, and with a central keratin plug. The greatest diameter of the lesion was 1.2 cm (Fig. 1). On surgical removal of the lesion, it was seen to be composed of a symmetric intradermal proliferation of cystic formations, uniformly distributed throughout and made up of flat, pluristratified epithelium with laminated keratin. There was little difference in the thickness of the walls of the cysts (Fig. 2). Some cysts were attached to a short tadpole-shaped, epithelial cord and surrounded by a scanty fibroblastic stroma. No hairmatrix-like differentiation nor basaloid structures were seen, nor were atypical cells present. There was hardly any inflammatory infiltration.