Low grade fibromyxoid sarcoma - Fine-needle aspiration cytology with histologic, cytogenetic, immunohistochemical, and ultrastructural correlation

BACKGROUND, Although the histologic features of the recently described low grade fibromyxoid sarcoma are well established, to the authors' knowledge t here are no reports in the literature describing the cytologic features of this tumor by fine-needle aspiration. Recognition of this lesion is importa nt because of its indolent but metastasizing nature. METHODS, The authors retrospectively reviewed their surgical pathology file s for cases of low grade fibromyxoid sarcoma with a preoperative fine-needl e aspiration biopsy (FNAB); three such cases were found. Immunohistochemica l studies were performed in all three tumors, ultrastructural examination w as performed in two tumors, and fresh tissue for cytogenetic analysis was o btained in one tumor. RESULTS, All FNABs showed similar features. The aspirates were relatively h ypocellular with an abundant myxoid background; the neoplastic cells contai ned oval to spindle shaped nuclei with minimal pleomorphism. No capillaries or areas of fibrous tissue were identified. Cytogenetic study of one case revealed no chromosomal abnormalities. The histologic findings were charact eristic for this lesion. By immunohistochemistry the tumor cells showed dif fuse and strong reactivity for vimentin only; at the ultrastructural level the neoplastic spindle cells had characteristics of fibroblasts. CONCLUSIONS. The cytologic features of low grade fibromyxoid sarcoma are no t specific enough for a definitive diagnosis based on FNAB alone; however, correlating the cytologic and clinical findings can narrow the range of dia gnosis. The differential diagnosis includes other myxoid lesions, in partic ular superficial or intramuscular myxoma and myxofibrosarcoma. In addition, the immunohistochemical and ultrastructural findings support a fibroblasti c origin for this neoplasm. (C) 1999 American Cancer Society.