Melanotic schwannoma of the lumbar spine: a case report and literature review

Abstract

Schwannomas are benign tumors, usually solitary, encapsulated, slow-growing, which have their origin in differentiated neoplastic Schwann cells with extramedullary intradural usual development related to nerve roots. The melanotic schwannoma is a variant of these tumors whose location in almost one third of cases is on the posterior spinal nerve root, with a nonspecific clinical presentation. Magnetic resonance imaging is the most widely used test for the diagnosis, revealing hyperintense T1-weighted sequences and hypointense T2-weighted sequences. Diagnostic confirmation is obtained by histological and immunohistochemical studies, in which there is intense cytoplasmatic pigmentation. There are two distinct types of melanotic schwannomas: sporadic and psammomatous, the latter related to the called Carney complex, a form of multiple endocrine neoplasm with familiar character. In literature we found few cases of these neoplasms, the largest series consisting of five cases. The objective of this study is to report a rare case of melanotic schwannoma of the lumbar spine of the sporadic type of extramedullary location. We also present a brief review of the literature containing the main characteristics of the tumor, including its different forms, differential diagnoses, data from histological and immunohistochemical studies as well as the currently recommended approach in order to contribute to a better understanding of this neoplasm.Keywords: Spine; Spinal neoplasms; Schwann Cells; Manipulation, spinal. RESUMO Os schwannomas são tumores benignos, geralmente solitários, encapsulados e de crescimento lento, que têm sua origem nas células de Schwann neoplásicas diferenciadas, com desenvolvimento habitual extramedular intradural relacionado com as raízes nervosas. O schwannoma melanocítico é uma variante dessas neoplasias cuja localização em quase um terço dos casos está na raiz nervosa posterior