Jugular foramen schwannoma: A rare tumor treated by stereotactic radiosurgery

Jugular foramen schwannomas (JFS) are rare benign tumors located in the jugular foramen. They can present with various symptoms depending on the extent of involvement of the tumor such as hearing loss, tinnitus, headache, and ataxia. Surgical resection has been considered as the primary treatment option for JFS. Stereotactic radiosurgery (SRS) offers an equally good treatment in patients with small and residual tumors after surgery with the advantage of being non-invasive with minimal complication rates. Herein, we present a rare case of JFS treated by SRS in our institution.

Submandibular region Schwannoma: A case report

Approximately 25-40% of the total schwannomas, are head and neck Schwannomas, they may originate from nerve sheath of the peripheral, cranial or autonomic nerves. We report a case of Schwannoma of right side Submandibular region in a 25 year old female with no significant dental, personal or medical history. Schwannomas are slowly progressive benign lesions, the patient presents with a mass or swelling that is growing in size slowly. The lesions are usually painless non-tender, smooth swelling beneath the mucosa with no changes in the overlying skin. An Ultrasound revealed well circumscribed hypoechoic solid lesion with internal vascularity. The lesion on T1 weighted MRI images exhibits homogenous isointensity and on T2 weighted MRI images exhibits heterogenous hyperintensity, on contrast enhanced T1 MRI images it exhibits salt and pepper type of enhancement. The diagnosis of Schwannoma is confirmed histopathologically by showing the presence of Antoni type A cells and Antoni type B cells, nuclear palisading, whirling of cells and Verocay bodies. This tumor may have originated from an autonomic nerve of the submandibular gland.

Complejo de Carney: reporte de un caso y revisión de la literatura / Carney complex: a case report and literature review

Resumen El complejo de Carney es una enfermedad caracterizada por lesiones en la piel, tumores endocrinos, cardiacos, gonadales y en otros órganos, que está asociada con mutaciones del gen PRKAR1A. Presentamos el caso clínico de una paciente con varias de las manifestaciones más características de este síndrome. Finalmente, se hace una revisión de la literatura.

Abstract Carney complex is a disease characterized by skin lesions, endocrine, cardiac, gonadal and other organ tumors, associated with mutations of the PRKAR1A gene. We present the clinical case of a patient with several of the most characteristic manifestations of this syndrome. Finally, there will be a review of the literature.

Our Management of Vestibular Schwannomas and Review of Literatures

There is no a clear consensus provided in the literature and there remain controversial on the treatment especially for small to medium size Vestibular schwannomas (VSs). Thus the treatment technique and approach preference vary from centre to centre. This problem too exists in our centre. The purpose of this paper is to develop a consensus in our hospital among our colleagues on the treatment of our VSs patients. We have been treating VSs patient by translabyrinthine approach from time to time for the last 5 years and found it to be a very efficient approach. This approach gives the most direct route to the tumor with excellent exposure of the internal acoustic meatus, cerebropontine angle (CPA) area without the need to retract the brain with facial nerve totally in control early in the surgery. The only problem was, when there is large posterior fossa component of the tumor present. This approach is safe with direct exposure to CPA area and have minimum intraoperative or postoperative 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)

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.

Neurilemoma pélvico benigno degenerado: Reporte de caso

Neurilemmomas are rare benign tumors derived from the peripheral nerve sheath and composed of perineural Schwann cells proliferating in a characteristic pattern. They are usually benign, slow-growing and often detected incidentally or by local symptoms secondary to compression of neighboring organs. These solitary tumors are located mainly in head and neck, frequently along the path of peripheral nerves, and are particularly rare as retroperitoneal and pelvic tumors. They represent less than 1% of pelvic tumors, and can reach large dimensions. Degenerated or ancient neurilemmomas present typical degenerative characteristics secondary to aging and decreased vascularization. These characteristics can lead to misinterpretation and confusion with a malignant lesion. Tumors are well encapsulated and recurrences are rare following complete surgical excision. The potential risk of surgical excision is neurological injury. We present the case of a degenerated benign pelvic neurilemmoma.

Los neurilemomas son tumores raros y benignos derivados de la vaina nerviosa periférica, compuesto por la proliferación de las células de Schwann perineurales con un patrón característico. Generalmente son benignos, de crecimiento lento y, con frecuencia, se les detecta de forma incidental o con síntomas locales secundarios a compresión de órganos vecinos. Estos tumores solitarios se localizan principalmente en cabeza y cuello, a menudo a lo largo del trayecto de los nervios y son particularmente raros entre los tumores retroperitoneales y de la pelvis. Los tumores pélvicos representan menos del 1% de todos los casos, pudiendo alcanzar grandes dimensiones. El neurilemoma degenerado o antiguo presenta características degenerativas típicas secundarias al envejecimiento y disminución de la vascularización. Todas estas características pueden llevar a la interpretación errónea y confundirlo con una lesión maligna. Los tumores están bien encapsulados y las recurrencias después de una escisión quirúrgica completa son poco frecuentes. La escisión quirúrgica conlleva el riesgo potencial de lesión neurológica. Presentamos un caso de neurilemoma pélvico benigno degenerado.

Vaginal schwannoma: report of a rare clinical case

Schwannomas of the female genital tract are extremely uncommon. They are usually benign, and simple excision is the adequate treatment. The case of a 57-year-old woman with a cellular schwan-noma of the vagina is described, in addition to a summarized literature review of schwannomas in the female genital tract. Complete excision was performed, and the histological report confirmed to be a vaginal Schwannoma. Due to its possibility to occur, even if in a very low incidence scenario, Schwan-nomas should not be excluded from the differential diagnosis of a vaginal mass. (AU)

Schwannomas do trato genital feminino são extremamente raros. São tumores geralmente benignos e a excisão simples é o tratamento adequado. Neste artigo descreve-se o caso de uma mulher de 57 anos com Schwannoma vaginal, além de uma revisão resumida da literatura sobre schwannomas no trato genital feminino. A excisão completa foi realizada e o estudo histológico confirmou o diagnóstico de Schwannoma vaginal. Devido à sua possibilidade de ocorrer, mesmo num cenário de incidência muito baixa, os Schwannomas não devem ser excluídos do diagnóstico diferencial de massas vaginais (AU)

Paracondylar-lateral cervical approach for resection of jugular foramen schwannomas: a retrospective analysis of 15 cases / 中华外科杂志

Objective@#To explore the effects of paracondylar-lateral cervical approach for resection of the jugular foramen schwannoma(JFS).@*Methods@#A total of 15 patients with JFS operated via the paracondylar-lateral cervical approach between December 2011 and March 2016 at Department of Neurosurgery in Xiangya Hospital of Central South University were retrospectively analyzed. There were 7 males and 8 females, aging from 22 to 77 years with a mean age of (41.9±15.8) years.There were 12 patients who accepted primary surgery, 3 patients who accepted secondary surgery. There were 10 patients with tinnitus or hearing loss, 8 patients with dysphagia, 9 patients with hoarseness, 7 patients with tongue hemiparesis, 8 patients with ataxia, 1 patient with Pyramidal signs, 2 patients with facial hypesthesia or pain, 1 patient with facial paresis. According to Samii JFS grading system, 2 patients were type B, 4 were type C and 9 were type D. All patients were followed-up through outpatient and telephone by MRI in 3, 9, 12 months postoperation.@*Results@#Gross total removal of tumors were achieved in 14 patients and subtotal removal in 1 patient. Two patients had new hoarseness, 2 had new dysphagia and 3 had more serious dysphagia, 1 patient had more serious facial paresis after the operation. There were 2 patients with intracranial infection, 2 with pneumonia, 1 with subcutaneous effusion, 1 with cerebrospinal fluid rhinorrhea, 5 with gastric intubation during perioperative period. There were no death, intracranial hematoma and decreased hearing patients. All patients were followed up, the follow-up time were 3 to 33 months with a mean of (26.9±11.2) months. Till to the latest follow up, dysphagia improved in 2 cases, hoarseness and tongue hemiparesis improved in 3 cases, hearing loss and tinnitus improved in 9 cases, balance function improved in 7 cases, facial hypesthesia and pain improved in 2 cases, pyramidal signs disappeared in 1 case, facial nerve function improved to normal in 1 case. There was no recurrence and progressed case.@*Conclusion@#Paracondylar-lateral cervical approach is an alternative approach for both intracranial and extracranial JFS.

Advances in the diagnosis and management of schwannomas in carotid space / 中国癌症杂志

Schwannomas of the vagus nerve (SVN) and schwannomas of the cervical sympathetic nerve (SSN) are the two most common schwannomas in the carotid space. Because schwannomas are asymptomatic, moreover, the vagus nerve and the cervical sympathetic nerve have adjacent anatomical location, it is diffcult to differentiate SVN or SSN. In addition, the current surgical treatment of schwannomas still remains controversial. This article summarized the studies on SVN and SSN, and meanwhile discussed the advances in the diagnosis and management of the disease.

Evaluación del Video Head Impulse Test (V-Hit) en el diagnóstico del neurinoma del acústico / Evaluation of video Head Impulse Test (v-HIT) in the diagnosis of acoustic neuroma

Introducción: La gran mayoría de lesiones que comprometen el conducto auditivo interno corresponden a schwannomas vestibulares (90%). Dentro de las nuevas pruebas diagnósticas del sistema vestibular aparece la prueba de impulso cefálico y su registro con el video Head Impulse Test (v-HIT) que permite el estudio de todos los canales semicirculares. Objetivo: Comparar el v-HIT para canales semicirculares laterales con las pruebas calóricas clásicas registradas mediante videonistagmografía en el comportamiento de los neurinomas intracanaliculares y evaluar su utilidad como test diagnóstico. Material y método: Dieciocho pacientes fueron reclutados con diagnóstico de neurinomas, confirmado mediante resonancia magnética y estudios con pruebas calóricas clásicas y v-HIT para canal horizontal. Resultados: Los resultados anormales de asimetría de ganancia y de sacadas correctivas fue de 13 pacientes (72%) y con hipoexcitabilidad en la prueba calórica fue de 9 pacientes (50%), con una sensibilidad de la prueba de 72% para vHIT y de 50% para la prueba calórica al compararlo con la resonancia magnética. Conclusión: El v-HIT es una herramienta complementaria a las pruebas calóricas y debe ser incluida como test diagnóstico dentro de la batería de exámenes para evaluar el sistema vestibular en forma completa mediante un vestibulograma.

Introduction: The majority of injuries involving the internal auditory canal correspond to vestibular schwannomas (90%). Within the new diagnostic tests for the vestibular system appears the Head Impulse test and the video head impulse test (v-HIT) which allows the studying of all the semicircular canals. Aim: Compare the v-HIT lateral semicircular canals with classical caloric tests recorded by videonistagmography (VNG) in the behavior of intracanalicular neuroma and evaluate its usefulness as a diagnostic test. Material and method: Eigtheen patients were enrolled with a diagnosis of schwannomas, confirmed by MRI and studied classical caloric tests and v-HIT for horizontal channel. Results: Abnormal results of asymmetry gain and corrective saccades was 13 patients (72%) and hypoexcitability in the caloric test was 9 patients (50%), with a test sensitivity of 72% for vHIT and 50% for caloric test compared with MRI. Conclusions: The v-HIT is a complementary tool to caloric tests and should be included as a diagnostic test within the battery of tests to evaluate the vestibular system in complete form by vestibulogram.

Endobronchial Schwannoma : A Rare Diagnosis.

Schwannomas are uncommon and often benign neoplasms developing from the nerve sheath of the peripheral nervous system. Thoracic schwannomas most often appear in the posterior mediastinum and costovertebral angle. Pulmonary schwannomas are exceedingly rare and can present a diagnostic challenge.Here we report a case of a solitary right-sided endobronchial schwannoma presenting with progressive respiratory symptoms and discuss the clinical features, histopathological manifestations and diagnostic considerations of this rare tumor.

Preoperative Identification of Facial Nerve in Vestibular Schwannomas Surgery Using Diffusion Tensor Tractography

OBJECTIVE: Facial nerve palsy is a common complication of treatment for vestibular schwannoma (VS), so preserving facial nerve function is important. The preoperative visualization of the course of facial nerve in relation to VS could help prevent injury to the nerve during the surgery. In this study, we evaluate the accuracy of diffusion tensor tractography (DTT) for preoperative identification of facial nerve. METHODS: We prospectively collected data from 11 patients with VS, who underwent preoperative DTT for facial nerve. Imaging results were correlated with intraoperative findings. Postoperative DTT was performed at postoperative 3 month. Facial nerve function was clinically evaluated according to the House-Brackmann (HB) facial nerve grading system. RESULTS: Facial nerve courses on preoperative tractography were entirely correlated with intraoperative findings in all patients. Facial nerve was located on the anterior of the tumor surface in 5 cases, on anteroinferior in 3 cases, on anterosuperior in 2 cases, and on posteroinferior in 1 case. In postoperative facial nerve tractography, preservation of facial nerve was confirmed in all patients. No patient had severe facial paralysis at postoperative one year. CONCLUSION: This study shows that DTT for preoperative identification of facial nerve in VS surgery could be a very accurate and useful radiological method and could help to improve facial nerve preservation.

Schwannomas vestibulares quísticos / Cystic vetibular schwannomas

Objetivo. Presentar nuestra experiencia en el tratamiento de los Schwannomas vestibulares quísticos comparándolos con lesiones sólidas. Material y método. Se evaluaron en forma retrospectiva los síntomas de presentación clínica, tasas de preservación facial, grado de resección quirúrgica, complicaciones postoperatorias y hallazgos histológicos de los Schwannomas quísticos pareados en base al tamaño tumoral con un grupo de lesiones sólidas. Resultados. Durante el período junio 1995 julio 2010, 27 pacientes con Schwannomas quísticos se operaron en nuestro Departamento. El diámetro promedio fue de 29,6 mm. Los síntomas de presentación clínica más frecuentes fueron la hipoacusia, inestabilidad en la marcha y parestesias faciales. Al año de cirugía, el 74% de los pacientes tenían función facial HB I-III sin diferencias significativas con el grupo de lesiones sólidas. La remoción completa fue 55,5% y 85% de los pacientes en las lesiones quísticas ysólidas respectivamente. Conclusión. Los Schwannomas quísticos deben ser evaluados en forma separada de las lesiones sólidas debido a que pueden crecer rápidamente, presentar mayor complejidad quirúrgica y desarrollar complicaciones postoperatorias con mayor frecuencia.

Objective. To present our experience treating this rare tumor variant.Material and Method. Retrospective evaluation of an institutional cystic vestibular schwannoma series, based on initial symptoms, rate of facial preservation, extent of surgical resection, postoperative complication rate and cystic lesion quantificationon histology in comparison to solid tumor type. Results. During the period June 1995-July 2010, 27 cysticschwannomas were operated on at the FLENI neurological Institute. Mean tumor diameter was 29,6mm. The most frequent presenting symptoms included hypoacusia, unsteadiness and facial paresthesias. One year after surgery, 74% of patients presented facial function HB I-III, showing no statistical difference in comparison to solid lesions. Complete surgical resectionwas possible in 55, 5% of the cystic and 85% of the solid tumor groups, respectively. Conclusion. Cystic vestibular schwannomas should be identified separately from vestibular schwannomas in general, particularlybecause they often undergo more rapid expansion, and may present greater surgical risk as well as higher rates ofpostoperative complications.

Laparoscopic Resection of a 12 cm Sized Retroperitoneal Schwannoma Adjacent to Retroperitoneal Vital Vessels: Are Large Retroperitoneal Schwannomas Not Suitable for the Laparoscopic Approach?

There are a lot of advantages to laparoscopic surgery, including early recovery, less postoperative pain, better cosmesis, shorter hospital stay and an early return to normal activities because of its minimal invasiveness. So, most surgeons have agreed on these points and have accepted the various indications for laparoscopic surgery. Despite these advantages and the recent advances in laparoscopic surgery, there are few cases using the laparoscopic approach for treating retroperitoneal schwannomas. Laparoscopic resection of a large retroperitoneal schwannoma has some difficulties for tumor retraction, dissecting around the large vessels, and removal of the resected tumor. Sometimes these difficulties may cause complications and a lengthened hospital stay. However, if appropriate methods are used, long hospital stay and complication can be prevented while maintaining the advantages of laparoscopic surgery.

Schwannomas intracraneanos: nuestra experiencia (2000-2009) / Intracraneal schwannomas: our experience (2000-2009)

Objective. To present and evaluate the surgical results in the treatment of intracranial schwannomas. Method. We present 26 patients with intracranial schwannomas for a period of 10 years treated with surgery, analyze kind ofpresentation and postoperative results. Results. One of the cases corresponded to schwanoma of III pair, another case to schwanoma of the V pair, two other cases corresponded to schwanoma of the IX pair and twenty two cases corresponded to schwanomas of the VIII pair. Average age was 51,95 años (19-73). Total resection was made in 25 patients, partial resection was made in other. Facial nerve preservation was made in the remaining 22 patients. Preservation auditory nerve function was made in all the cases. We had 3 cases of cerebrospinal fluid leak.There were no mortal cases associated to the surgical procedure. Conclusion. The goal of treatment of intracranial schwanomas is total resection with anatomical and functional preservation of neurological structures around. This could be accomplished by retrosigmoid approach by experienced neurosurgeons.

Tumores intradurales extramedulares primarios tratados en el Instituto Nacional de Rehabilitación / Primary intradural extramedullary tumors treated at the National Institute of Rehabilitation (Mexico)

Introducción: Los tumores de la columna son lesiones poco comunes que afectan a una porción menor de la población, sin embargo, pueden causar morbilidad significativa y estar asociados a mortalidad. Representan 15 % de los tumores craneoespinales. El objetivo del presente trabajo fue definir la frecuencia de tumores intradurales extramedulares de columna vertebral en el Servicio de Cirugía de Columna Vertebral del Instituto Nacional de Rehabilitación, y su diagnóstico histopatológico definitivo. Material y métodos: Estudio retrospectivo de una serie de pacientes tratados quirúrgicamente entre 1996 y 2006 por diagnóstico de tumor intradural extramedular. Se evaluó sexo, edad, localización, sintomatología y tipo de tumor. Resultados: Se revisaron 27 pacientes, 11 hombres y 16 mujeres, con edad promedio de 47.33 años. Los síntomas principales fueron dolor y pérdida de la fuerza. La localización más frecuente fue la torácica seguida de la lumbar; el diagnóstico histopatológico indicó meningioma en 12 casos, schwannoma en 12 y neurofibroma en tres. Conclusiones: La sintomatología, localización y predominio de sexo son similares a los informados en la literatura. A diferencia de otras series, los tumores más frecuentes en la nuestra fueron schwannomas y meningiomas. Es importante el diagnóstico oportuno y tratamiento adecuado, que en nuestros pacientes consistió en resección total con laminoplastia, para evitar secuelas neurológicas permanentes.

BACKGROUND: Spine tumors are uncommon injuries affecting a low percentage of the population; however, these tumors can cause significant morbidity and may be related to mortality. They represent 15% of craniospinal tumors. The objective of this study is to determine the frequency of intradural extramedullary spine tumors treated in our Service and to report the definitive histopathological diagnosis. METHODS: This was a retrospective study in a series of patients treated surgically with a diagnosis of intradural extramedullary tumor in the Spine Service of the National Rehabilitation Institute (Mexico) from 1996 to 2006. The following variables were evaluated: gender, age, tumor localization, symptomatology and type of tumor. RESULTS: Files of 27 patients were reviewed. There were 11 men and 16 women with an average age of 47.33 years. The main symptoms were pain and motor weakness. The most frequent localization was thoracic followed by lumbar. Histopathological diagnosis reported 12 cases of meningioma, 12 cases of schwannoma and 3 cases of neurofibroma. CONCLUSIONS: Symptomatology, localization and gender predominance are similar to that reported in the literature. Different from other series, schwannomas and meningiomas were the most frequent tumors in our study. Appropriate diagnosis and opportune treatment consisting of total resection with laminoplasty are crucial in order to avoid permanent neurological consequences.

Aspectos histoquímicos e imunoistoquímicos nos neoplasmas do sistema nervoso periférico / Histochemical and immunohistochemical features of peripheral nerve neoplasms

Doze casos de tumores do sistema nervoso periférico, sete schwannomas e cinco neurofibromas foram diagnosticados entre 1964 e 2004, em caninos e bovinos. Histologicamente, as células predominantes nos schwannomas eram fusiformes organizavam-se em paliçada ou em feixes aleatórios. Nos neurofibromas as células neoplásicas eram fusiformes e se originavam da periferia dos nervos formando ninhos e feixes. O tecido conjuntivo era mais abundante nos neurofibromas e os colágenos dos tipos I e III eram os principais constituintes desses neoplasmas. Os neurofibromas foram caracterizados por uma concentração alta e difusa de mastócitos, provavelmente devido à origem das células neoplásicas do perineuro e epineuro. A coloração de AgNOR não se mostrou eficiente como indicador de prognóstico nos neoplasmas analisados. Imunoistoquímicamente houve forte marcação para vimentina (100 por cento) e S100 (100 por cento) em ambos os tipos de tumor. A maioria dos schwannomas (75 por cento) foi positiva para a proteína ácida fibrilar glial; os neurofibromas só apresentaram marcação nas células de Schwann dos fascículos nervosos

A retrospective study of peripheral nerve tumors was made from 1964 to 2004. The tumors summed up 12, being seven schwannomas and five neurofibromas. Schwannomas were composed of spindle-shaped cells either in a palisading pattern or random bundles loosely textured and neurofibromas by spindle cells. The connective tissue components were more prevalent in neurofibromas with a characteristic deployment of collagens type I and III. In AgNOR techniques, both benign and malignant schwannomas and neurofibromas did not show differences. Mast cells stained by toluidine blue were more prevalent in neurofibromas which are rich in reactive endoneurium. Schwannomas (100 percent) and neurofibromas (100 percent) were positive for vimentin and S100 protein, so they prove to be reliable for the diagnosis of peripheral nerve tumors. GFAP marked cells were found in three schwannomas and in Schwann cells within neurofibromas

Extrahepatic Biliary Schwannomas: A Case Report

Benign schwannomas arise in neural crest-derived Schwann cells. They can occur almost anywhere in the body, but their most common locations are the central nervous system, extremities, neck, mediastinum, and retroperitoneum. Schwannomas occurring in the biliary tract are extremely rare and mostly present with obstructive jaundice. We recently experienced a case of extrahepatic biliary schwannomas in a 64-yr-old female patient who presented with intra- and extrahepatic bile duct and gallbladder stones during a screening program. To the best of our knowledge, extrahepatic biliary schwannomas associated with bile duct stones have not been reported previously in the literature.

Long-term Outcomes of Gamma Knife Stereotactic Radiosurgery of Vestibular Schwannomas

OBJECTIVE: Gamma Knife Stereotactic Radiosurgery (GK SRS) has become an important treatment modality for vestibular schwannomas. We evaluated the tumor control rate, patterns of tumor volume change and preservation of hearing following low-dose radiation for vestibular schwannomas in a homogeneous cohort group in which the mean marginal dose was 12 Gy. METHODS: A total of 59 patients were enrolled in this study. All enrolled patients were followed-up for at least 5 years and the radiation dose was 11-13 Gy. Regular MRI, audiometry and clinical evaluations were done and tumor volumes were obtained from MRI using the OSIRIS program. RESULTS: The tumor control rate was 97%. We were able to classify the patterns of change in tumor volume into three categories. Transient increases in tumor volume were detected in 29% of the patients and the maximum transient increase in tumor volume was identified at 6 to 30 months after GK SRS. The transient increases in tumor volume ranged from 121% to 188%. Hearing was preserved in 4 of the 12 patients who had serviceable hearing prior to treatment. There were no other complications associated with GK SRS. CONCLUSION: Low-dose GK SRS was an effective and safe mode of treatment for vestibular schwannomas in comparison to the previously used high-dose GK SRS. Transient increases in tumor volume can be identified during the follow-up period after low-dose GK SRS for vestibular schwannomas. Physicians should be aware that these increases are not always indicative of treatment failure and that close observation is required following treatments. Unfortunately, a satisfactory hearing preservation rate was not achieved by reducing the radiation dose. It is thought that hearing preservation is a more sophisticated problem and further research is required.