Percutaneous needle biopsy diagnosis of benign neurogenic neoplasms

Abstract

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 diagnosing schwannomas and neurofibromas, 40 percutaneous biopsies interpreted as BNNs or obtained from lesions subsequently shown by excision to be BNNs were reviewed. The 13 aspirates diagnostic of BNN revealed spindle cells arranged haphazardly in irregular tissue fragments and in parallel as elongated ropy fascicles, with a myxoid to fibrillary background. The nuclei were buckled, often with intranuclear cytoplasmic inclusions. Four lesions showed nuclear pleomorphism without mitoses. Of 19 schwannomas evaluated by FNA, four (21%) were diagnosed as schwannomas and seven (37%) as BNNs. Ten neurofibromas were aspirated, revealing two (20%) BNNs. Of seven nondiagnostic FNAs accompanied by NCB, three (43%) indicated a BNN. The sensitivities of FNA, NCB, and both modalities in diagnosing BNNs were 43, 60, and 71%, respectively. For the 16 FNAs showing features of BNNs, subsequent excisions revealed 11 schwannomas, two neurofibromas, one neurogenic sarcoma, one fibromyxoid neoplasm of uncertain malignant potential, and one unclassified low‐grade myxoid sarcoma. FNA can be effective in diagnosing BNNs. If collagenous 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 may show nuclear pleomorphism without mitotic activity, and should not be mistaken for sarcoma. Diagn. Cytopathol. 16:17–25, 1997. © 1997 Wiley‐Liss, Inc.

Fine‐needle aspiration cytology versus core‐needle biopsy for the diagnosis of extracranial head and neck schwannoma

“…2,3,7,15 However, in 28 cases with satisfactory specimens in the present study, the sensitivity was 64.3% (18/28), which represents an acceptable diagnostic performance. These results were similar to those of previous studies that evaluated FNAC for the diagnosis of schwannoma, which reported unsatisfactory specimen rates of 36%-50% and sensitivity rates of 0%-40%.…”

“…Therefore, obtaining an accurate preoperative diagnosis, preferably while identifying the nerve of origin, is critical for establishing an appropriate management plan for this type of tumor. 3,7 Moreover, immunohistochemical staining, which is usually critical for the diagnosis of schwannoma, is unavailable for cytological specimens harvested using FNAC. 5,6 Although this technique is easily available and highly accurate for most head and neck masses, the diagnostic sensitivity of FNAC for schwannomas is relatively low at 0%-40%, and also too often produces unsatisfactory specimens.…”

Cytomorphologic features that distinguish schwannoma from other low‐grade spindle cell lesions

“…Aspirates from neurofibroma are frequently nondiagnostic . The current series contained a single atypical neurofibroma.…”

“…Distinguishing low‐grade malignant peripheral nerve sheath tumor may be challenging, even after surgical resection has been performed. On FNAB material, cellular dissociation is a helpful diagnostic feature, because it is observed for the most part in malignant tumors . If adequate tissue is available, the presence of diffuse and intense immunoreactivity for S‐100 protein or SOX10 is also useful, because spindle cell malignant peripheral nerve sheath tumors rarely exhibit strong S‐100 protein or SOX10 reactivity …”

On the utility and limitations of fine-needle aspiration of palpable lesions located in the hand

“…In the anatomic region of the hand, cytologically we have occasionally mistaken leiomyomas for schwannomas and dermatofibromas, and we have missed neurofibromas. Resnick et al 27 pointed out the low sensitivity of cytology in the recognition of benign neurogenic tumors.…”