Cavitary melanoma of the ciliary body. A study of eight cases.

Purpose: The authors present the unique clinical features of cavitary uveal melanoma.
Design: Retrospective chart review.
Participants: Eight patients with cavitary uveal melanoma.
Main Outcome Measures: The clinical, ultrasonographic, and histopathologic features of eight patients with cavitary melanoma of the ciliary body were studied.
Results: In all eyes there was a brown ciliary body mass that blocked transmission of light on trans-scleral transillumination. Ocular ultrasonography revealed a large, single hollow cavity (unilocular "pseudocyst") in five cases and multiple hollow cavities (multilocular "pseudocyst") in three cases. The cavity occupied a mean of 55% of the entire mass thickness (range, 31%-79%). In five cases, a basal uveal mass was noted on ultrasonography. Four patients underwent tumor resection; one had enucleation, and three had 125I radioactive plaque treatment. In the five cases confirmed histopathologically, the cavitation was empty, contained erythrocytes, serous fluid, and/or pigment-laden macrophages. In no case was the cavity lined by necrotic tumor, endothelial cells, or epithelial cells.
Conclusion: Ciliary body melanoma can develop an intralesional cavity resembling an intraocular cyst. The presence of a solid mass at the base and a thick wall surrounding the cavity can assist in the differentiation of cavitary melanoma from benign cyst.