Alveolar soft part sarcoma. A case report with correlation of fine needle aspiration and ultrastructural cytologic features.

Tissue from an alveolar soft part.sarcoma (ASPS) was studied, and a comparison was made between the morphologic features found on light microscopy histology, fine needle aspiration (FNA) cytology and electron microscopy. The characteristic findings seen in FNA of ASPS (alveolar aggregates, capillary networks, eccentric nuclei with prominent nucleoli, intranuclear vacuoles, cytoplasmic zonation, intracellular and exocytosed magenta granules, sharply defined and thickened cell border) are supported by the ultrastructural findings and, although not totally specific, can serve as sensitive markers in order to raise the suspicion of this rare neoplasm in the appropriate clinical setting. A differential diagnostic discussion is included, supporting the above conclusion.