Trichoblastic fibroma of the eyelid.

Trichoblastic fibroma (TBF), also known as trichoblastoma, small nodular type, is a rare benign cutaneous adnexal tumor that shows trichogenic (follicular) differentiation that can be mistaken clinically and histologically for basal cell carcinoma (BCC), a locally aggressive trichogenic carcinoma. As the clinical behaviors of these two follicular neoplasms are opposite from one another and their management is thus different, recognition of TBF is crucial for effective therapy. Although TBF most commonly is first seen on the face, this lesion has not previously been reported in the eyelid. In this report, we document the first case of TBF affecting the ocular adnexa and detail the histologic features that differentiate TBF from BCC.