Tricholemmoma of the eyelid.

Tricholemmoma is a benign cutaneous tumor that shows differentiation characteristic of the outer hair sheath. The usual site of occurrence is the face, including the nose and eyelid. Four cases of tricholemmoma involving the eyelid margin to a variable extent are presented and the clinical and pathologic findings are reviewed. In three of the four cases, a histopathologic misdiagnosis of squamous cell carcinoma was initially made. In one case, this resulted in a greater sacrifice of normal lid tissue than was necessary, although the reconstruction yielded a good result. In the subsequent cases, the entity of tricholemmoma was well appreciated before definitive oculoplastic surgery and the referring diagnosis of squamous cell carcinoma was refuted.