Chordoid Tumor: A Light, Electron Microscopic, and Immunohistochemical Study

Chordoid tumor-synonymous with chordoid sarcoma, parachordoma, and peripheral chordoma-is a very rare neoplasm with histologic similarity to chordoma that is found outside the axial skeleton. A soft tissue chordoid tumor in the gluteus maximus muscle of a 42-year-old man is presented. This tumor had morphologic features identical to a chordoma: nodular growth with vacuolated cytoplasm and myxomatous stroma by light microscopy, positive immunoreaction for cytokeratin and epithelial membrane antigen by immunohisto-chemistry, desmosomes, intercellular lumina lined with microvilli, and the presence of basal lamina material by electron microscopy. Two similar cases have been reported in the English literature.