Balloon cells were found to represent a significant histologic component of a spindle cell malignant melanoma of the choroid. Review of 200 cases of malignant melanoma of the choroid and ciliary body revealed that the incidence of balloon cells in these tumors was 10% and that such cells were more commonly present in spindle cell tumors.
Riley FC. Balloon Cell Melanoma of the Choroid. Arch Ophthalmol. 1974;92(2):131-133. doi:10.1001/archopht.1974.01010010137011