Clinicopathological analysis of extracranial head and neck schwannoma: A case series

Abstract

Background: Extracranial head and neck schwannomas are rare tumors which are often clinically misdiagnosed. Preoperative diagnosis of these tumors is challenging but imperative for surgeons so as to avoid nerve damage during excision. Materials and Methods: Sixteen patients diagnosed with extracranial head and neck schwannomas over a period of 2 years were retrospectively analyzed. Clinical details including preoperative fine-needle aspiration cytology (FNAC) and/or computed tomography (CT)/magnetic resonance imaging (MRI) findings were retrieved. FNAC smears and formalin-fixed paraffin-embedded sections were evaluated. Results: Among these 16 tumors, 6 (37.5%) were located in the lateral aspect of neck, 4 (25%) in scalp, 2 (12.5%) in orbit, and one each (6.25%) in palate, tongue, submandibular gland and parotid gland. The mean patient age was 31.3 years. FNAC was performed in 14 cases, of which 8 cases (58.3%) showed features of benign nerve sheath tumor (BNST), two cases (14.2%) were inconclusive with possibility of mesenchymal lesion, two cases (14.2%) were inadequate, one case (8.3%) showed features suggestive of schwannoma, and a diagnosis of nerve sheath tumor inconclusive for malignancy was rendered in a single case. The sensitivity of FNAC in diagnosis of BNST was 71.4%. CT or MRI was performed in five cases, of which an accurate diagnosis was rendered only in one case of orbital schwannoma. Conclusion: Imaging has a limited role in the preoperative diagnosis of head and neck schwannomas owing to nonspecific radiological features. Cellular aspirate smears are helpful in accurate diagnosis even at unusual locations.