[Retroperitoneal schwannoma mimicking colorectal cancer metastases: a false positive result report.] / Schwannoma retroperitoneal simulando metástasis de cáncer colorrectal: reporte de un resultado falso positivo.

Introduction: schwannomas are benign and common soft tissue tumors. They are usually asymptomatic and are discovered for other reasons. Materials: we present the case of an 82-year-old male patient with a recent diagnosis of moderately differentiated adenocarcinoma of the colon and a hypermetabolic periaortic nodule as an incidental finding. Results: percutaneous biopsy of the periaortic nodule confirmed the diagnosis of schwannoma. At one year of follow-up, growth of the schwannoma has been demonstrated. There are no signs of progression of his oncological disease. Conclusions: schwannomas are benign tumors, rarely found in the retroperitoneum and can be sources of false-positive positron emission tomography results.

Introducción: los schwannomas son tumores benignos y frecuentes de las partes blandas. Habitualmente son asintomáticos y son descubiertos por otros motivos. Materiales y métodos: presentamos el caso de un paciente masculino de 82 años con diagnóstico reciente de adenocarcinoma de colon moderadamente diferenciado y con un nódulo periaórtico hipermetabólico como hallazgo incidental. Resultados: la biopsia percutánea del nódulo periaórtico confirmó el diagnóstico de schwannoma. Al año de seguimiento, se ha demostrado crecimiento del schwannoma. No hay signos de progresión de su enfermedad oncológica. Conclusión: los schwannomas son tumores benignos, infrecuentes en el retroperitoneo y pueden ser fuentes de resultados falsos positivos en tomografía por emisión de positrones.

Feasibility study of ResNet-50 in the distinction of intraoral neural tumors using histopathological images.

BACKGROUND: Neural tumors are difficult to distinguish based solely on cellularity and often require immunohistochemical staining to aid in identifying the cell lineage. This article investigates the potential of a Convolutional Neural Network for the histopathological classification of the three most prevalent benign neural tumor types: neurofibroma, perineurioma, and schwannoma. METHODS: A model was developed, trained, and evaluated for classification using the ResNet-50 architecture, with a database of 30 whole-slide images stained in hematoxylin and eosin (106, 782 patches were generated from and divided among the training, validation, and testing subsets, with strategies to avoid data leakage). RESULTS: The model achieved an accuracy of 70% (64% normalized), and showed satisfactory results for differentiating two of the three classes, reaching approximately 97% and 77% as true positives for neurofibroma and schwannoma classes, respectively, and only 7% for perineurioma class. The AUROC curves for neurofibroma and schwannoma classes was 0.83%, and 0.74% for perineurioma. However, the specificity rate for the perineurioma class was greater (83%) than in the other two classes (neurofibroma with 61%, and schwannoma with 60%). CONCLUSION: This investigation demonstrated significant potential for proficient performance with a limitation regarding the perineurioma class (the limited feature variability observed contributed to a lower performance).

Combined open maxillectomy and endoscopic endonasal resection of a giant V2 trigeminal schwannoma.

BACKGROUND: Trigeminal schwannoma is a rare type of tumor that arises from the Schwann cells of the trigeminal nerve. METHOD: We present a case of a patient with a giant V2 trigeminal schwannoma with painful swelling in the left maxilla. A complete resection using a combined open maxillectomy and endoscopic endonasal approach was performed. CONCLUSION: This case highlights the importance of a multidisciplinary approach to perform a combined open and endoscopic approach for safe resection while preserving adequate speech and swallowing.

[Malignant melanotic nerve sheath tumor of the posterior mediastinum]. / Tumor maligno melanocítico de la vaina neural en mediastino posterior.

Melanotic schwannoma (MS) is a rare and infrequent subtype of schwannoma characterized by cytoplasmic deposits of melanosomes (melanin). Unlike the other schwannomas, it could have malignant transformation. Due to distinctive characteristics and atypical behavior from classic schwannomas subtypes, MS were renamed and reclassified as "melanocytic malignant neural sheath tumor" in the 5th ed. of the World Health Organization's classification of central nervous system tumors in 2021. We present two cases of MS that underwent complete surgical resection.

El schwannoma melanótico (SM) es una variante rara e infrecuente caracterizada por el depósito citoplasmático de melanosomas (melanina). A diferencia de las otras variantes de schwannomas, tienen capacidad de malignización. Por poseer características y comportamiento distintos al resto de los schwannomas, fue reclasificado como "tumor maligno melanocítico de la vaina neural" en la 5ta edición de la clasificación de los tumores del sistema nervioso central de la Organización Mundial de la Salud en 2021. Presentamos dos casos de SM de ubicación mediastinal en los que se realizó una resección quirúrgica completa.

Robotic-Assisted Resection of a Benign Schwannoma of the Obturator Nerve: A Rare Case.

BACKGROUND Neurilemmomas are rare tumors derived from the Schwann cells that comprise the peripheral nerve sheaths. They have a slow growth and rarely display malignancy. Early diagnosis is rare, and the treatment consists by surgical resection. Although robotic-assisted surgery is commonly used for treating retroperitoneal diseases, there are few reports of resection of retroperitoneal and pelvic schwannoma through robotic-assisted surgery. In the present study, we reported a case of complete excision of a benign retroperitoneal schwannoma of the obturator nerve by robotic-assisted surgery. CASE REPORT A 51-year-old woman was referred by her gynecologist for left pelvic discomfort of a 3-month duration. The physical examination was normal, but a computerized tomography scan of the abdomen and pelvis showed an expansive pelvic lesion in the topography of the left iliac vessels, a hypodense contrast enhancement measuring 4.6×3.4 cm. Magnetic resonance imaging showed an extraperitoneal lesion located medially and inferiorly to the left external iliac vessels, with a size of 4.9×3.7 cm, and of probable neural etiology. Surgical resection of the tumor was recommended because of the diagnostic hypothesis of obturator nerve schwannoma. CONCLUSIONS This case showed that retroperitoneal neurilemmomas are difficult to diagnose owing to a lack of specific symptoms, and the best treatment is complete tumor resection. The use of robotic techniques gives greater dexterity to the surgeon, since it provides high-definition 3-dimensional vision, which can make the removal of retroperitoneal tumors susceptible to minimally invasive resection in a safe and effective way.

Benign cervical schwannoma with tracheal invasion.

Schwannomas commonly develop in the cervical region, 25% - 45% of cases are diagnosed in this anatomical region. Tracheal neurogenic tumors are exceedingly rare and can be misdiagnosed as invasive thyroid carcinomas or other infiltrating malignancies when present at the level of the thyroid gland. Here, we present a case of synchronous benign cervical schwannoma with tracheal invasion and papillary thyroid carcinoma in a patient who was initially hospitalized for COVID-19. The patient presented with dyspnea that was later found to be caused by tracheal extension of a cervical tumor. Surgical excision was performed, and the surgical team proceeded with segmental tracheal resection, removal of the cervical mass, and total thyroidectomy. The specimen was sent for pathological analysis, which revealed synchronous findings of a benign cervical schwannoma with tracheal invasion and papillary thyroid carcinoma. The literature on this subject, together with the present case report, suggests that neurogenic tumors should be included in the differential diagnosis of obstructing tracheal cervical masses. Surgical excision is the first-line of treatment for benign cervical schwannomas.

Minimally Invasive Approaches for Lumbosacral Plexus Schwannomas.

BACKGROUND AND OBJECTIVES: Lumbosacral plexus schwannomas (LSPSs) are benign, slow-growing tumors that arise from the myelin sheath of the lumbar or sacral plexus nerves. Surgery is the treatment of choice for symptomatic LSPSs. Conventional retroperitoneal or transabdominal approaches provide wide exposure of the lesion but are often associated with complications in the abdominal wall, lumbar or sacral plexus, ureter, and intraperitoneal organs. Advances in technology and minimally invasive (MIS) techniques have provided alternative approaches with reliable efficacy compared with traditional open surgery. We describe 3 MIS approaches using tubular retractor systems according to the lesion level. METHODS: This was a multicenter, retrospective observational cohort study to evaluate the use of MIS tubular approaches for surgical resection of LSPSs. We included 23 lumbar and upper sacral plexus schwannomas. Clinical presentation, spinal level, surgical duration, degree of resection, days of hospitalization, pathological anatomy of the tumor, approach-related surgical difficulties, and outcomes were collected. RESULTS: The posterior oblique approach was used in 43.5% of the cases, the transpsoas approach in 39.1%, and the transiliac in 17.4%. The mean operative time was 3.3 hours, and the mean hospitalization was 2.5 days. All tumors were WHO grade 1 schwannoma. Postoperative MRI confirms gross total resection in 91.3% of the patients. No patient requires instrumentation. The pros and cons of each approach were summarized. CONCLUSION: The MIS approaches adapted to the lumbar level may improve surgeons' comfort allowing a safe resection of retroperitoneal LSPS.

Clinical Characteristics and Surgical Outcomes of 2542 Patients with Spinal Schwannomas: A Systematic Review and Meta-Analysis.

OBJECTIVE: This study was conducted to systematically analyze the data on the clinical features, surgical treatment, and outcomes of spinal schwannomas. METHODS: We conducted a systematic review and meta-analysis under the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A search of bibliographic databases from January 1, 2001, to May 31, 2021, yielded 4489 studies. Twenty-six articles were included in our final qualitative systematic review and quantitative meta-analysis. RESULTS: Analysis of 2542 adult patients' data from 26 included studies showed that 53.5% were male, and the mean age ranged from 35.8 to 57.1 years. The most common tumor location was the cervical spine (34.2%), followed by the thoracic spine (26.2%) and the lumbar spine (18.5%). Symptom severity was the most common indicator for surgical treatment, with the most common symptoms being segmental back pain, sensory/motor deficits, and urinary dysfunction. Among all patients analyzed, 93.8% were treated with gross total resection, which was associated with better prognosis and less chance of recurrence than subtotal resection. The posterior approach was the most common (87.4% of patients). The average operative time was 4.53 hours (95% confidence interval [CI], 3.18-6.48); the average intraoperative blood loss was 451.88 mL (95% CI, 169.60-1203.95). The pooled follow-up duration was 40.6 months (95% CI, 31.04-53.07). The schwannoma recurrence rate was 5.3%. Complications were particularly low and included cerebrospinal fluid leakage, wound infection, and the sensory-motor deficits. Most of the patients experienced complete recovery or significant improvement of preoperative neurological deficits and pain symptoms. CONCLUSIONS: Our analysis suggests that segmental back pain, sensory/motor deficits, and urinary dysfunction are the most common symptoms of spinal schwannomas. Surgical resection is the treatment of choice with overall good reported outcomes and particularly low complication rates. gross total resection offers the best prognosis with the slightest chance of tumor recurrence and minimal risk of complications.

Posterior Interosseous Nerve Syndrome due to Schwannoma - A Case Report / Síndrome interóssea posterior devido a schwannoma - Um relato de caso

Abstract Posterior interosseous nerve syndrome is the most frequent syndrome of radial nerve compression, with the arcade of Frohse being the main site of compression. Its symptoms include difficulties in finger and wrist extension with possible radial deviation. Herein, we present a case of posterior interosseous syndrome caused by a schwannoma, a type of neurological tumor.

Resumo A síndrome interóssea posterior é a síndrome mais frequente de compressão do nervo radial, com a arcada de Frohse sendo o principal local de compressão. Seus sintomas incluem dificuldades na extensão do dedo e punho, com possível desvio radial. Aqui, apresentamos um caso de síndrome interóssea posterior causada por um schwannoma, um tipo de tumor neurológico.

A Rare Case of a Schwannoma on the Foot - Case Report / Caso raro de um schwannoma no pé - Relato de caso

Abstract A Schwannoma is an infrequent lesion. This tumor derives from the myelin sheath of the peripheral nerves; in most cases, it is benign and rarely presents in the foot and ankle region. Patients affected by this type of pathology are usually asymptomatic. Still, they sometimes have sensory or motor neurologic symptoms if the tumor is large enough to cause direct or indirect compression of the affected nerve. A 55-year-old male patient presented to our department with non-traumatic swelling and pain in the lateral aspect of the right foot and leg. A magnetic resonance imaging (MRI) scan of the right leg revealed a well-circumscribed lesion, measuring 2,5 by 1 cm, showing hypointensity on T1 sequences and hyperintensity on T2, compatible with a superficial peroneal nerve sheath cells tumor. Surgical excision of the lesion was performed, and the histopathological examination confirmed the initial suspicion—Schwannoma of the superficial peroneal nerve. The postoperative period was uneventful, with progressive improvement of pain and complete functional recovery without neurological deficits. Rigorous clinical examination associated to MRI scans allow adequate diagnosis as well as the exclusion of other pathologies with similar clinical presentation. Thus, the surgeon has to be aware of all the data for an effective diagnosis and treatment in this type of rare pathology that cannot be neglected.

Resumo Um schwannoma é uma lesão pouco frequente, sendo um tumor que deriva da bainha de mielina dos nervos periféricos; na maioria dos casos, este tumor é benigno e raramente se apresenta na região do pé e tornozelo. Os pacientes afetados por esse tipo de patologia são geralmente assintomáticos. Ainda assim, às vezes eles têm sintomas neurológicos sensoriais ou motores se o tumor for grande o suficiente para causar a compressão direta ou indireta do nervo afetado. Um paciente do gênero masculino de 55 anos se apresentou ao nosso departamento com inchaço não traumático e dor no aspecto lateral do pé direito e da perna. A ressonância magnética (RM) da perna direita revelou uma lesão bem-circunscrita, medindo 2,5 por 1 cm, mostrando hipointensidade nas sequências T1 e hiperintensidade em T2, compatível com um tumor superficial de células do nervo peronal. Foi realizada excisão cirúrgica da lesão e o exame histopatológico confirmou a suspeita inicial - Schwannoma do nervo peroneal superficial. O pós-operatório foi tranquilo, com melhora progressiva da dor e recuperação funcional completa sem déficits neurológicos. Exame clínico rigoroso associado aos exames de RM permitem diagnóstico adequado, bem como a exclusão de outras patologias com apresentação clínica semelhante. Assim, o cirurgião tem que estar atento a todos os dados para um diagnóstico e tratamento eficazes nesse tipo de patologia rara que não pode ser negligenciada.

Dificultad diagnóstica en masa retroperitoneal. Reporte de un caso / Diagnostic difficulty in retroperitoneal mass: A case report

El Schwannoma se origina de la vaina perineural de Schwannoma, se detecta con frecuencia incidentalmente en estudios imagenológicos siendo el principal método diagnóstico la Tomografía Computada. El tratamiento es la resección quirúrgica con márgenes libres. Se presenta una paciente femenina de 49 años, en control por oncología por enfermedad de base, cáncer de mama izquierda, se identifica por TAC y PECT/TC imagen voluminosa en retroperitoneo situación lateroaórtica izquierda de configuración no quística e hipermetabólica, solicita biopsia percutánea, ante la falta de ventana, se decide exeresis completa de masa. Diagnóstico definitivo patológico Schwannoma. Sin indicación de tratamiento adyuvante, cursa buena evolución postoperatoria sin recidiva.

Schwannoma, a benign tumor that arises from Schwann cells of the perineural nerve sheath, is often incidentally detected in imaging tests and mainly diagnosed by CT scan. Treatment consists of surgical resection with clear margins. We present the case of a 49-year-old female patient subject to Oncology Department follow-up due to an underlying disease, left breast cancer. A large, hypermetabolic, noncystic mass in the retroperitoneal region is identified by CT and PECT/CT scan in the left lateral aortic area. A percutaneous biopsy is requested. Due to the limited acoustic window, complete resection of the mass is decided. Final histopathology diagnosis of Schwannoma. No adjuvant treatment indication; undergoing favorable postoperative progress, without recurrence

Surgical outcome of spinal schwannoma and neurofibroma.

OBJECTIVE: The aim of this study was to evaluate the outcome and surgical complications in patients with spinal schwannoma or neurofibroma surgically treated at the Hospital das Clínicas of the State University of Campinas. METHODS: This was a retrospective cohort study, using medical records of patients operated between 2011 and 2021. The sample distribution was verified using the Kolmogorov-Smirnov test. The dynamics between qualitative variables were assessed using Fisher's exact test. We used means analysis to assess patient improvement based on Frankel scores. RESULTS: A total of 16 patients were evaluated, of whom 56.25% (9) were men and 43.75% (7) were women. There were 13 (81.25%) patients with schwannomas and 3 (18.75%) with neurofibromas. Patients with deficits had neurological improvement, such as walking or with at least Frankel D or E after surgery. Laminectomy, performed in 8 patients (50%), and laminoplasty, used in 9 patients (56.25%), were the main techniques. CONCLUSION: The surgical approach was proved to be an effective and safe alternative to the treatment of these tumors, with neurological improvement and minor surgical complications.

Carbon-Assisted Minimally Invasive Transtubular Approach for Intercostal Nerve Schwannoma.

BACKGROUND AND OBJECTIVES: The intraoperative localization of an intercostal nerve schwannoma (INS) is extremely difficult because the lesion is generally not palpable, and the fluoroscopic visualization of anatomic landmarks in the ribs is unsatisfactory. Using activated carbon suspension to mark the soft-tissue approach could improve INS localization. We present a novel, simple, reproducible carbon-assisted minimally invasive transtubular approach for an INS. METHODS: The patient was a 57-year-old man with a painful 12th left INS arising below the floating rib. A computed tomography image-guided, tumor-to-skin marking with aqueous carbon suspension was performed 48 hours before surgery. A minimally invasive transtubular approach following the carbon path allowed a precise tumor location. RESULTS: The INS was completely removed. The patient's thoracic radicular pain was immediately relieved after surgery. He was discharged the following day with residual numbness on the left thoracic side. At the 5-year follow-up, no tumor recurrence was noted in the control MRI. CONCLUSION: This article presents an alternative novel technique for resecting an intercostal schwannoma. Using a transtubular approach with carbon-marking assistance allowed a tumor gross total resection with immediate pain relief and a successful outcome.

Schwannoma gigante de pelvis: Reporte de Caso / Giant pelvic Schawannoma: A case report

Introducción: Los Schwannomas son tumores derivados de las células de Schwann que se pueden presentar en cualquier lugar de la economía corporal, siendo poco usual su localización en la pelvis (1 a 3 %). Con presentación tórpida y sintomatología variada en relación con el sitio que ocupan. Su tratamiento se basa en la resección quirúrgica. Caso clínico: Presentamos el caso de un hombre joven de 21 años presentando dolor pélvico por 4 meses. Taller diagnóstico: en imágenes se evidencia una masa que ocupa toda la pelvis, esta es extirpada y revela como diagnóstico histopatológico. Neoplasia mesénquimal compatible con schwannoma. Conclusión: En conclusión, estos tumores son raros, y la localización pélvica es muy poco frecuente, su extirpación se vuelve curativa y debe realizarse de manera oportuna.

Introduction: Schwannomas are tumors derived from Schwann cells that can occur anywhere in the body economy, and their location is unusual in the pelvis (1 to 3%). With torpid presentation and varied symptoms about the site they occupy. Its treatment is based on surgical resection. Clinical case: We present the case of a 21-year-old man with pelvic pain for four months. Diagnostic workshop: Images show a mass that occupies the entire pelvis; this is removed and revealed as a histopathological diagnosis. Mesenchymal neoplasm compatible with schwannoma. Conclusion: In conclusion, these tumors are rare, and the pelvic location is very infrequent; their removal becomes curative and must be performed promptly.

Schwannoma intraóseo en fémur, una presentación inusual. Reporte de caso / Intraosseous Schwannoma in femur, an unusual presentation. Case report

El Schwannoma o Neurilemoma es un tumor benigno de derivación neuroectodérmica que se origina en las células de Schwann, que constituyen la envoltura de los nervios. Es el tumor benigno más común de los nervios periféricos, tiene predisposición a originarse a partir de nervios periféricos sensoriales y puede presentarse como tumores en tejidos blandos. La presentación intraósea del Schwannoma es rara y corresponde al 0,2% de los tumores óseos primarios. Se presenta caso clínico de paciente masculino de 36 años de edad con tumor en cóndilo femoral medial de rodilla derecha de 4 años de evolución, cursando con dolor intermitente moderado a quien se le practicó el protocolo oncológico, imagenológico e histológico, de la Unidad de Oncología Ortopédica del estado Monagas. Se diagnosticó Schwannoma intraóseo, se procedió a realizar resección marginal y reconstrucción con alloinjerto y fijación con placa y tornillos con excelente evolución postoperatoria. El Schwannoma intraóseo es extraordinariamente raro y su ubicación en el fémur lo es aún más. El objetivo del presente trabajo es reportar un caso de Schwannoma Intraóseo, mostrar las estrategias para su diagnóstico y los tratamientos aplicados, así como la revisión de los datos al respecto existentes en la literatura(AU)

Schwannoma or Neurilemoma is a benign tumor of neuroectodermal derivation that originates in Schwann cells, which constitute the nerve sheath. It is the most common benign tumor of the peripheral nerves, has a predisposition to originate from peripheral sensory nerves, and can present as soft tissue tumors. The intraosseous presentation of Schwannoma is rare and corresponds to 0,2% of primary bone tumors. A clinical case of a 36-yearold male patient with a tumor in the medial femoral condyle of the right knee of 4 years of evolution is presented, presenting with moderate intermittent pain who underwent the oncological, imaging and histological protocol of the Oncology Unit. Monagas State Orthopedic. Intraosseous Schwannoma was diagnosed, marginal resection and allograft reconstruction and plate and screw fixation were performed with excellent postoperative evolution. Intraosseous Schwannoma is extraordinarily rare and its location in the femur is even more so. The objective of this paper is to report a case of Intraosseous Schwannoma, show the strategies for its diagnosis and the treatments applied, as well as the review of the existing data in the literature(AU)