Balloon cell metastatic melanoma: an important differential in the diagnosis of clear cell tumours.

Two cases of metastatic balloon cell melanoma are reported. Each tumour was composed of large clear cells which did not contain melanin, glycogen or fat, but showed positive staining for S-100 protein, NK/1-C3 and HMB-45. In each case the primary lesion was a cutaneous melanoma of typical morphology. It is essential to consider balloon cell melanoma in the differential diagnosis of clear cell tumours. These cases emphasize the need for an accurate clinical history.