Balloon cell melanomas of the ciliary body.

In spite of the fact that balloon cell change has been recognized ophthalmoscopically and histologically in certain posterior choroidal melanomas, the nature and importance of this observation remain controversial. This article provides a clinicopathologic correlation in two cases of ciliary body melanoma with almost total balloon cell transformation. On the basis of special stains and electron microscopic observations, we have concluded that balloon cells in such cases represent spindle melanoma cells that have undergoing extensive cytoplasmic lipid metamorphosis. The possible mechanisms for this change are considered. Melanomas containing an abundant number of balloon cells are probably comparatively dormant and benign tumors that offer a relatively good prognosis. Although clinical recognition may be difficult, the use of needle biopsy coupled with cytologic diagnosis in selected ciliary body tumors may disclose balloon cell change and help to direct therapy.