Fine-needle aspiration of leiomyosarcoma: a correlative cytohistopathological study of 96 tumors in 68 patients.

Abstract

To better define the cytological features of various leiomyosarcoma (LMS) variants, we reviewed the fine-needle aspiration material and the corresponding histologic sections of 96 tumors in 68 patients. Histological variants of LMS were as follows: 80 (83.3%) were of the classical/usual, seven (7.3%) were epithelioid, and nine (9.4%) were myxoid. Review of original cytology reports showed that 23 (24%) tumors were diagnosed as LMS and 69 (71.8%) as other types of malignancies. Two (2.1%) cases were reported as suspicious and two (2.1%) were unsatisfactory. The classical variants of LMS were characterized cytologically by various proportions of spindle-shaped, cohesive, small- or large-sized cells arranged in parallel alignment. Large spindle, round, binucleated, giant cells with intracytoplasmic granulations were frequently seen. Blunt-ended nuclei, intranuclear inclusions and mitotic figures were occasionally seen, as well as stromal fragments. The epithelioid tumors were composed of an admixture of small and large, spindle-shaped and round cells, also arranged in parallel alignment. Tumor cells with granular cytoplasm, blunt-ended nuclei, intranuclear inclusions, mitotic figures, fibrous or myxoid stroma were not observed. The myxoid tumors disclosed large amounts of background myxoid matrix containing large spindle-shaped and giant cells. Entities such as leiomyoma, malignant peripheral nerve sheath tumor, monophasic synovial sarcoma, and malignant fibrous histiocytoma should be considered in the differential diagnosis of LMS of the classical type. Epithelioid leiomyoma may share similar cytological features with epithelioid LMS. The cytological features of the myxoid variant of LMS can be easily confused with other types of benign and malignant mesenchymal tumors depicting degenerative myxoid changes and/or a myxoid matrix component.