FINE-NEEDLE ASPIRATION BIOPSY - PITFALLS IN THE DIAGNOSIS OF SPINDLE-CELL LESIONS

Seven cases of spindle-cell proliferations in which fine-needle aspira tion biopsy (FNAB) did not correlate with subsequent histology are pre sented. Three cases were considered low-grade sarcoma, one a dermatofi brosarcoma protuberans (DFSP), one a spindle-cell tumor with malignanc y not excluded, and one a rhabdomyosarcoma vs. a fibrosarcoma. Two of the these three were histologically nodular fasciitis and one an infla mmatory pseudotumor. Two cases were diagnosed cytologically as fibroma tosis or nodular fasciitis (NF). One of these histologically was an in tramuscular hemangioma, the other a DFSP. The last two cases were diag nosed by FNAB as spindle-cell lesion, undetermined if benign or malign ant, and malignant fibrous histiocytoma (MFH). Histologically both of these case were leiomyosarcoma. The cytologic features of each case, d ifferential diagnosis, and potential pitfalls are discussed In the eva luation of FNAB smears dominated by spindle cells, cellullarity, indiv idual cells and cell patterns, and background stromal features coupled with a precise clinical history may allow a narrow differential diagn osis with a focus on whether the lesion is benign or malignant. Cautio n is warranted in the exact classification of spindle-cell tumors from FNAB as this may have a major impact on patient management. (C) 1994 Wiley-Liss, Inc.