Fine-needle aspiration of epithelioid sarcoma - Cytology findings in nine cases

BACKGROUND. Epithelioid sarcoma is a rare tumor with characteristic morphol ogic and immunohistochemical features. It can be confused histologically an d cytologically with a variety of benign and malignant lesions, including a granulomatous process, synovial sarcoma, melanoma, squamous cell carcinoma , and adenocarcinoma. The objective of this study was to define the cytolog ic features of this rare tumor. METHODS. The cytologic features of nine histologically confirmed epithelioi d sarcomas were analyzed. The criteria evaluated included cell size and sha pe, cell borders, cluster organization, cytoplasmic characteristics, nuclea r and nucleolar features, and background characteristics. RESULTS. in most cases, single, dispersed cells represented the predominant pattern, with only a few small clusters present. The cells were mostly rou nd with interspersed spindle cells and mild to moderate pleomorphism. The n uclei were large and eccentrically located, with a plasmacytoid appearance. A pale zone in the perinuclear area was evident in three of nine cases. We ll-defined cell borders with intercellular spaces between malignant cells w ere observed in eight cases. In three cases, a granuloma-like structure was identified. In two cases, the cells were mostly spindle and showed greater cellular pleomorphism. CONCLUSION. Epithelioid sarcoma is an uncommon tumor with a wide range of d ifferential diagnoses, especially in cytology specimens. Awareness of its e xistence and knowledge of its cytologic features are important for a correc t diagnosis. (C) 2001 American Cancer Society.