Orbital squamous cell carcinoma after retinal detachment surgery.

We report on a 76-year-old patient with a squamous cell carcinoma of the left orbit. The tumour had no connection with the conjunctiva but was located at the site of an encircling band which had been inserted 13 years before. A major part of the tumour presented as a well circumscribed solid mass within the extraocular tissues next to the inferior equator, but the exenteration specimen also showed tumour extension within the adjacent choroid. Histological examination showed a well differentiated keratinising squamous cell carcinoma with numerous mitotic figures and many epithelial pearls. A thorough examination in search of a primary carcinoma of the lacrimal gland or the sinus, with invasion into the orbit, or an epithelial neoplasm elsewhere suggestive of metastatic disease into the choroid did not reveal any specific pathological findings. Thus the most probable origin of the tumour seems to be epithelium which had been misplaced during retinal detachment surgery and had subsequently undergone malignant transformation.