Caracterização imuno-histoquímica das neoplasias primárias do sistema nervoso periférico (SNP) em gatos

Abstract

Primary neoplasms of the peripheral nervous system are rare in domestic animals, and are rarely, reported in cats. They are classified, according to cellular origin most frequently into schwannomas, neurofibromas, perineuriomas and malignant peripheral nerve sheath tumor (MPNST). For diagnosis, histopathological examination is used as standard, but the association with histochemical and immunohistochemical (IHC) techniques are necessary for accuracy in the diagnosis. Epidemiological data on the occurrence and anatomical location of these neoplasms are rarely described in Brazil. Therefore, the objective of this study is to classify by histopathology and immunohistochemistry the neoplasms of the peripheral nervous system of cats sent for diagnosis at the Veterinary Pathology Sector of the Federal University of Lavras, over a period of 16 years; to the Veterinary Diagnostic Center – Celulavet, Belo Horizonte – MG, over a period of four years; and to Patologia Veterinária do Vale – PatoVetVale, Taubaté – SP, over a period of two years. During this period, 2536 histopathological examinations were carried out on felines, affected by different pathologies. Among these, 55 cutaneous and subcutaneous neoplasms previously diagnosed and graded as schwannoma and soft tissue sarcoma, grades I, II and III, were selected, which were subjected to IHC labelling with primary antibodies anti-GFAP (glial fibrillary acidic protein), -NSE (neuron specific enolase), -Neurofilament, -S-100 and -NGFR (nerve growth factor). Among the 55 neoplasms, 34 were considered to originate in the SNP, representing 1.34% of the pathologies diagnosed in felines. Thirty-four neoplasms showed positive multifocal staining for the antibody anti -GFAP, and of these, 28 also marked for anti-NSE, nine for anti-S100, three for anti-NF and 13 for anti-NGFR. Based on morphological and IHC findings, 13 neoplasms were classified as Schwannomas and 21 as MPNST. It was concluded that primary SNP neoplasms are uncommon, affect mainly elderly cats, of no defined breed and without sex predilection. The most affected location was the head and chest region and MPNST was the most diagnosed tumor. The recommended antibodies for the IHC diagnosis of these neoplasms are GFAP, S-100 and NGFR, however, due to varied immune reactivity, the search for more specific markers must continue.