[Nikolowski's trichoadenoma]

A 50 year old male patient is reported who had an asymptomatic nodule on the left pre-auricular region for about one year. The nodule, clinically diagnosed as an epidermoid cyst, was excised. Histologically it was an intradermal lesion composed of multiple keratinous cysts and solid epithelial nests and masses, malpighian in type. The lesion was imbedded in a well organized stroma, was separated from the overlying epidermis by a superficial dermal band and did not elicit any inflammatory response. No basaloid masses or strands with a lace-like arrangement nor attempts at hair formation could be seen. The differential diagnosis and nosological autonomy of trichoadenoma are discussed and the relevant literature is briefly reviewed.