Peripheral Nerve Schwannomas: A Literature Review

Introduction Schwannomas are benign tumors originating from the cells, which wrap around axons that are usually encapsulated and solitary. These tumors usually lead to little or no symptomatology. They are usually the most common peripheral nerve tumors in adults, with their highest incidence between the third and fifth decades of life. Objective To perform a review about schwannoma of the peripheral nerves, presenting its definition, epidemiology, diagnosis, symptomatology and treatment. Methodology This is a descriptive work, based on a review of articles available in the PubMed database with the descriptors schwannoma and peripheral nerves. Results and Discussion Only papers published between 1981 and 2019, describing studies in humans, and that were available as full articles were selected. A total of 391 articles were included; after reading the titles, we noted that 67 articles fit the topic of the present study. Among the articles selected for reading, 33 fit the objectives of the present work, and were considered for the writing of the present article. Conclusion Schwannomas are benign myelin sheath tumors that develop with local symptomatology or asymptomatic and present a good surgical prognosis with generally reduced rates of surgical complications.

Neurofibromatosis tipos 1 y 2 / Neurofibromatosis type 1 and 2

La neurofibromatosis (NF) comprende un grupo de enfermedades genéticas de herencia autosómica dominante, que se clasifican de la siguiente manera: neurofibromatosis tipo 1 (NF1), neurofibromatosis tipo 2 (NF2) y schwannomatosis (también conocida como neurofibromatosis tipo 3). Esta última es una enfermedad muy infrecuente, con una prevalencia aproximada de 1/126 000 personas, por lo que solo profundizaremos las dos primeras. La NF1, también conocida como la enfermedad de Von Recklinghausen, es la más frecuente de las tres y afecta principalmente la piel y el sistema nervioso periférico. Se caracteriza por la presencia de máculas "café con leche", pecas axilares o inguinales, nódulos de Lisch (hamartomas en el iris) y neurofibromas (tumores de la vaina de nervios periféricos). Otras manifestaciones menos frecuentes, aunque de mayor gravedad, incluyen gliomas del nervio óptico, meningiomas, neurofibromas malignos, escoliosis y displasia de la tibia. Su diagnóstico se suele realizar al nacimiento o durante los primeros años de vida, y se estima que un 50% de quienes la padecen presenta dificultades cognitivas. No hay datos concluyentes sobre la mortalidad en los pacientes con NF1, aunque se sabe que la expectativa de vida es menor que en la población general. La NF2 tiene una prevalencia considerablemente menor que la NF1 y su inicio es más tardío, afectando principalmente a adultos jóvenes. La presentación clínica típica se caracteriza por acúfenos, hipoacusia y ataxia en contexto de la presencia de schwannomas vestibulares bilaterales. Otros hallazgos menos frecuentes incluyen schwannomas de nervios periféricos, meningiomas, ependimomas o astrocitomas. La esperanza de vida es de unos 36 años, con una supervivencia media desde el momento del diagnóstico de 15 años. (AU)

Neurofibromatosis (NF) includes a group of genetic diseases with an autosomal-dominant inheritance pattern, and they are classified as follows: Neurofibromatosis type 1 (NF1), neurofibromatosis type 2 (NF2) and Schwannomatosis (also known as neurofibromatosis type 3). This last one is a very rare disease, with an approximate prevalence of 1/126000, so we will only deepen in the first two. NF1, also known as von Recklinghausen disease, is the most frequent, and mainly affects the skin and peripheral nervous system. Its typical manifestations are the presence of café-au-lait macules, axillary or inguinal freckles, Lisch nodules (hamartomas in the iris) and neurofibromas (peripheral nerve sheath tumors). Less frequent manifestations, although more serious, include optic nerve gliomas, meningiomas, malignant neurofibromas, scoliosis and tibial dysplasia. The diagnosis is usually made at birth or during the first years of life, and approximately 50% of patients present cognitive difficulties. There is no conclusive data on mortality in patients with NF1, although it is known that life expectancy is lower than in general population. NF2 has a considerably lower prevalence than NF1, and its onset is later in life, mainly affecting young adults. Its typical clinical presentation is characterized by tinnitus, hearing loss and ataxia in the context in the presence of bilateral vestibular schwannomas. Less frequent findings include peripheral nerve schwannomas, meningiomas, ependymomas or astrocytomas. Life expectancy is about 36 years old, with a median survival from the moment of diagnosis of 15 years. (AU)

Intradural Schwannoma Exacerbating the Symptoms of Degenerative Lumbar Stenosis: Case Report

Introduction Schwannoma is a common intradural slow-growing, benign and encapsulated tumor that originates from the myelin sheaths of the nerve fibers. However, a lumbar schwannoma complicating the symptoms of spinal stenosis is an extremely rare association. Aim To describe the case of a woman presenting a lumbar schwannoma in association with spinal stenosis. Case Report A 53 year-old female was referred to neurosurgical evaluation due to the worsening of a lumbar pain that was irradiating to the left inferior leg along the anterolateral surface. A neurological examination revealed motor deficits for extension of the left leg and attenuation of the left patellar reflex. Magnetic resonance imaging (MRI) showed lumbar spinal stenosis due to flavum ligament hypertrophy and disc herniation in the L3L4 and L4L5 segments, and an expansive lesion with homogeneous contrast enhancement occupying the left neuroforamen of the L3L4 segment. The patient underwent surgical resection of the tumor and decompression of the stenotic segments with posterior screw instrumentation from L3 to L5. She presented an uneventful recovery and significant improvement of the lumbar pain, and was still free of symptoms 6 months after surgery. An anatomopathological examination defined the tumor as a schwannoma (Grade I ­ World Health Organization [WHO]). Conclusion The present study highlights that lumbar schwannoma is a possible etiology complicating the symptoms of patients with previous lumbar spinal stenosis. It is important to treat both pathologies to improve the patients' symptoms.

Introdução O schwannoma é um tumor intradural comum, benigno, de crescimento lento e encapsulado que se origina da bainha de myelina das fibras nervosas. No entanto, a presença de um schwannoma lombar complicando os sintomas de estenose do canal medular é uma associação extremamente rara. Objetivos Descrever o caso de uma paciente portadora de schwannoma lombar exacerbando os sintomas de estenose do canal lombar. Relato de Caso Uma mulher de 53 anos de idade foi encaminhada para avaliação neurocirúrgica devido a relato de piora dos sintomas de dor lombar que irradiavam preferencialmente para o membro inferior esquerdo na sua face antero-lateral. O exame físico neurológico revelou a presença de déficit motor para a extensão do membro inferior esquerdo e redução do reflexo patelar esquerdo. A imagem de ressonância magnética mostrou a presença de estenose do canal lombar devido à hipertrofia do ligamento amarelo e herniações discais nos segmentos L3L4 e L4L5. Além disso, o estudo radiológico também evidenciou a presença de uma lesão expansiva ocupando o neuroforamen de L3L4 com captação homogênea do meio de contraste. A paciente foi submetida à ressecção cirúrgica do processo neoplásico e descompressão do canal medular com artrodese através de instrumentação dos segmentos L3L4L5 via posterior em um único ato operatório. A paciente apresentou uma recuperação pós-operatória adequada e mantém-se assintomática em segmento clínico seis meses após o procedimento cirúrgico. O estudo anatomo-patológico e imuno-histoquímico definiu o processo expansivo como schwannoma (Grau I da OMS). Conclusão O presente estudo destaca que o schwannoma lombar é uma possibilidade etiológica para os pacientes portadores de estenose do canal lombar que apresentam piora progressiva dos sintomas ou novos déficits neurológicos. É importante tratar as duas patologias para que o paciente obtenha melhor resultado clínico no controle dos sintomas.

Hallazgo clínico de un Schwannoma: presentación de un caso y revisión bibliográfica / Schwannoma as a clinical finding: report of a clinical case and review of the literature

El schwannoma es un tumor benigno compuesto por células de Schwannque se localizan preferentemente en los pares craneales VIII y X, es de uncrecimiento lento. Son tumores muy bien delimitados ya que poseen una cápsula fibrosa y tienen consistencia blanda y gelatinosa. En este artículo le presentaremos un caso de un paciente de 56 años, que por hallazgo radiográfico presentaba un Schwannoma con origen en elNervio Dentario Inferior, rama terminal del Trigémino.

case of intraparenchymal occipital lobe Schwannoma in Shiraz, Southern Iran

One case of intraparenchymal Schwannoma of right occipital lobe is presented [first report of occipital lobe Schwannoma]. The radiological and pathological features of this rare tumor are discussed, and the current theories for etiology of these intraaxial nerve-sheath tumors are reviewed

Neurilemoma o Schwannoma benigno: presentación de un caso clínico / Neurilemoma or benign Schwannoma: presentation of a case

Se presenta un caso de Neurilemoma o Schwannoma, de ubicación retroperitoneal, intervenido por uno de nosotros en un paciente de 21 años de edad. Como es común en esta patología, los síntomas ocurrieron mucho tiempo después de advertirse la presencia del tumor; siendo los mas significativos el dolor y gran movilidad. Esto último hizo plantear la factibilidad de tumor intraperitoneal. Las íntimas relaciones que presentaba el tumor con el pedículo renal, vena cava inferior, columna y músculos psoas, no impidieron hacer la exceresis completa del mismo, lo cual fue posible mediante disección cuidadosa. El ecosonograma y tomografía computarizada, señalaron su situación retroperitoneal; pero concluían tratarse de un teratoma por las áreas de calcificación. La clínica, paraclínica y aspecto macroscópico, no fueron suficiente para hacer el diagnóstico definitivo. Solo el estudio microscópico detectó la existencia de Areas A y B de Antoni, lo cual histológicamente es característica del Neurilemoma o Schwannoma benigno

Malignant schwannoma occurring with Schistosoma japonicum: a case report.

An 18-year-old Filipina presented with a 28 cm retroperitoneal malignant schwannoma arising from the sigmoid colon. Histopathologic examination revealed the presence of numerous schistosome ova immediately adjacent to the tumor and throughout the submucosa. Due to the rarity of malignant schwannomas, their infrequent occurrence in young persons in the absence of von Recklinghausen's neurofibromatosis, and the presence of schistosomal ovideposition, the possible role of schistosomal infection in the development of this malignancy is discussed. This is the first reported case of a malignant schwannoma occurring together with schistosomiasis.