PERCUTANEOUS NEEDLE-BIOPSY DIAGNOSIS OF BENIGN NEUROGENIC NEOPLASMS

Preoperative diagnosis of benign neurogenic neoplasms (BNNs) provides useful information in guiding management. To assess the effectiveness of fine-needle aspiration (FNA) and needle core biopsy (NCB) in diagno sing schwannomas and neurofibromas, 40 percutaneous biopsies interpret ed as BNNs or obtained from lesions subsequently shown by excision to be BNNs were reviewed. The 13 aspirates diagnostic of BNN revealed spi ndle cells arranged haphazardly in irregular tissue fragments and in p arallel as elongated ropy fascicles, with a myxoid to fibrillary backg round. The nuclei were buckled often with intranuclear cytoplasmic inc lusions. Four lesions showed nuclear pleomorphism without mitoses. Of 19 schwannomas evaluated by FNA, four (21%) were diagnosed as schwanno mas and seven (37%) as BNNs. Ten neurofibromas were aspirated revealin g two (20%) BNNs. Of seven nondiagnostic FNAs accompanied by NCB, thre e (43%) indicated a BNN. The sensitivities of FNA, NCB, and both modal ities in diagnosing BNNs were 43, 60, and 71%, respectively For the 16 FNAs showing features of BNNs, subsequent excisions revealed 11 schwa nnomas, two neurofibromas, one neurogenic sarcoma, one fibromyxoid neo plasm of uncertain malignant potential, and one unclassified low-grade myxoid sarcoma. FNA can be effective in diagnosing BNNs. If collageno us or myxoid lesions yield paucicellular nondiagnostic aspirates, NCB is helpful. Low-grade sarcoma and neurofibromatous areas of neurogenic sarcoma may be misinterpreted as BNNs by percutaneous biopsy. BNNs ma y show nuclear pleomorphism without mitotic activity, and should not b e mistaken for sarcoma. (C) 1997 Wiley-Liss, Inc.