Abstract
To evaluate the accuracy and reproducibility of subgrouping and grading soft‐tissue sarcomas by fine‐needle aspiration biopsy (FNAB), a blind review was conducted of 84 FNAB specimens from 77 malignant and 7 benign soft‐tissue lesions. Cytomorphologic subgroups included 31 spindle‐cell, 24 pleomorphic, 11 myxoid, 7 epithelioid/polygonal, 3 small round cell, and 8 nondiagnostic cases. Malignancies included one lymphoma and 41 primary, 15 recurrent, and 20 metastatic soft‐tissue sarcomas. Adequacy was defined as a majority of slides with at least 5 clusters of 10 unobscured cells. Five originally false‐negative cases were considered nondiagnostic on review. Sarcoma was recognized in 59 of 64 adequate cases (92%) with available histology; however, the specific histopathologic subtype was identified in only 9 cases (14%). Benign myxoid and spindle‐cell lesions were difficult to separate from low‐grade sarcomas in 4 cases, and a B‐cell lymphoma with sclerosis mimicked a low‐grade myxoid sarcoma. The assigned cytologic grade accurately reflected the histologic grade in 90% of sarcomas when segregated into high and low grades. Pleomorphic, small round cell, and epithelioid/polygonal subgroups corresponded to high‐grade sarcomas in all cases with only minor noncorrelations. Major grading noncorrelations occurred in 50% of myxoid and 9% of spindle‐cell sarcomas. Therefore, attention should be given to specimen adequacy, and caution should be exercised when attempting to grade myxoid and spindle‐cell sarcomas by FNAB. Diagn. Cytopathol. 24:307–316, 2001. © 2001 Wiley‐Liss, Inc.