Schwannoma and its unusual variants-A histopathological study

Abstract

Background: Schwannomas exhibit histologic features that may overlap with those of benign and malignant peripheral nerve sheath tumours. This can be the challenging in making accurate histopathological diagnosis there by influence clinical management. Objective: Our study focuses on schwannomas to identify subtypes based on histopathologic attributes and associated clinical features and its variants. Methods: 37 cases of schwannoma were ascertained using records (2003 to 2006) and also prospectively (2006-2008) at JJM Medical college hospital, Davangere. Case and specimen details, slides and blocks were collected from department archives. The specimens were fixed in 10% formalin for 24-48 hours and sampled for detailed histopathological examination. Slides were stained with hematoxylin and eosin. Microscopic findings were noted in a detailed manner in a proforma. Special staining with Perl’s Prussian blue, toluidine blue and immunohistochemistry were performed wherever needed. Results: Classical schwannomas comprised most cases, 31 (83.8%). Histological variants encountered were cellular schwannoma, plexiform schwannoma, ancient schwannoma, schwannoma with pseudoglandular elements, cystic schwannoma and psammomatous schwannoma. Most common locations of classical schwannomas were head & neck region followed by extremities, seen over a wide age range. In only one case of classical schwannoma, histopathological diagnosis correlated with clinical diagnosis. Conclusion: Schwannomas show an interesting histologic variety despite being composed of a limited array of cellular constituents. Key issue for the pathologist includes distinguishing schwannomas from neurofibromas, and MPNSTs from cellular schwannoma or neurofibromas. Keywords: Schwannoma, Peripheral nerve, Histopathology