Extraskeletal myxoid chondrosarcoma with intranuclear vacuoles and microtubular aggregates in the rough endoplasmic reticulum. Report of a case with fine needle aspiration and electron microscopy.

The findings of fine needle aspiration biopsy cytology, histology, immunohistochemistry and electron microscopy in an extraskeletal myxoid chondrosarcoma of the soft tissue of the thigh detected in a 65-year-old man are described. In addition to the more usual cytologic findings of chondroblasts and pleomorphic mesenchymal cells, this tumor displayed distinctive intranuclear cytoplasmic inclusions and microtubular aggregates in the rough endoplasmic reticulum. Cytologic study made the diagnosis of malignancy, suggesting a myxoid sarcoma; the precise diagnosis was made by the subsequent studies on the resected tumor and resin-embedded samples of the aspirate. The suitability of aspirated material in the differential diagnosis of myxoid soft tissue tumors is discussed.