Intestinal Clear Cell Sarcoma With Melanocytic Differentiation and Extraskeletal Myxoid Chondrosarcoma Rearrangement: Report of a Case

A clear cell sarcoma-like tumor with osteoclast-like giant cells of the gastrointestinal tract without immunoexpression of CD117 was recently proposed as a new tumor entity. In this article, a case of a 37-year-old man with a neoplasm of the jejunum composed of polygonal cells with clear to eosinophilic cytoplasm forming nests and fascicles is reported. Giant cells were not identified. Immunohistochemically, the tumor cells expressed strongly S100 protein, human melanoma black 45, platelet-derived growth factor receptor α, B-cell lymphoma 2, p53, and to a lesser extent vimentin, neuron-specific enolase, and epithelial membrane antigen. Mindbomb homolog-1 index was 35%. Immunoreactivity for CD34 and CD117 was negative. The fluorescence in situ hybridization analysis showed a translocation involving chromosome 22q12, the diagnostic hallmark of clear cell sarcoma of soft tissues. This case indicates a close histogenetic relationship with the recently reported clear cell sarcoma with osteoclast-like giant cells of the gastrointestinal tract, as well as with the clear cell sarcoma of soft tissues.