Clear cell tumors of the somatic soft tissues

The prototypic soft tissue tumor showing "clear" cytoplasmic features is the so-called clear cell sarcoma or malignant melanoma of soft parts, a tumor characterized by immunophenotypic and ultrastructural melanogenic differentiation and specific cytogenetic and molecular abnormalities, ie, t(12;22)(q13;q12) translocation and Ewing's sarcoma oncogene/activating transcription factor 1 rearrangement. A number of other malignant soft tissue tumors occasionally show cytoplasmic clarity, including epithelioid leiomyosarcomas, malignant peripheral nerve sheath tumors, and sclerosing fibrosarcomas, as well as metastatic carcinomas and malignant melanomas. These tumors are discussed in relation to their differential diagnosis with clear cell sarcomas.