Primary squamous cell carcinoma arising from an epithelium-lined cyst of the lacrimal gland.

A 66-year-old man presented with a slowly enlarging, nontender left orbital mass of 2 months' duration. CT and MRI showed a left lacrimal gland mass with enhancement and internal irregularity of cystic structures. Histopathologic analysis of the biopsy specimen revealed a squamous cell carcinoma arising from an epithelium-lined cyst. The patient underwent left orbital exenteration followed by radiation treatment. No evidence of tumor recurrence was observed after a follow-up of 30 months. We believe this primary squamous cell carcinoma may have arisen either from preexisting lacrimal duct cyst (dacryops) with areas of squamous metaplasia or, less likely, from a choristomatous epithelium-lined cyst of the lacrimal gland. Although rare, this entity should be included in the differential diagnosis of cystic lesions of the lacrimal gland.