Balloon cell malignant melanoma of the choroid: ultrastructural studies.

I reported the clinical, pathological, and ultrastructural findings in 2 cases of balloon cell malignant melanoma of the choroid. Degradation of the melanosomes of the tumour cells appeared to be the primary biological disturbance in the cell organelles, followed by secondary increase in intracellular lipid secretion and accumulation, leading ultimately to the formation of the balloon cells. Despite the fact that balloon cells are indicative of degeneracy and impending necrosis of the tumour cells, metastases were present in both cases. One of the conclusions this article provides is that the presence of balloon cells does not alter the prognosis of malignant melanomas of the choroid.