[Soft-tissue malignant melanoma (clear-cell sarcoma). Description of 2 cases with unusual histological features]

Malignant melanoma of soft part. Report of two cases with unusual histological features. Two examples of malignant melanoma of soft parts (clear cell sarcoma) are reported. In the first case the tumor cells showed predominantly eosinophilic cytoplasms; positive staining for S-100 protein has been observed immunohistochemically in the majority of the tumor cells. The second case, in recurrent lesion, showed a prominent "balloon cell" transformation of tumor cells. The clinico-pathologic picture, differential diagnosis and histogenetic problems are also discussed.