BackgroundGiant cell ependymoma of the filum terminale is a rare variant, generally manifested as a well-circunscribed intradural mass with an indolent biological behavior.Case presentationWe describe the case of a 48-year-old Mexican female who non-relevant past medical history, that developed a GCE of the filum terminale. Magnetic resonance imaging and computed tomography revealed the presence of an intra-axial tumor extending from L3 to L5 with extra-medullary invasion. Therefore the tumor was considered unresectable and only incisional biopsy was obtained, establishing the tentative diagnosis of a poorly differentiated neoplasia. A second evaluation of the case revealed the presence of numerous non-cohesive pleomorphic giant cells with intranuclear inclusions and broad eosinophilic cytoplasm, alternating with intermediate size cells with round, hyperchromatic nuclei and forming a perivascular pseudo-rosettes pattern. The ependymal phenotype was supported by light microscopy and corroborated by immunohistochemistry analysis. The patient was subsequently treated with radiotherapy 54Gy. She is alive after a 27-month follow-up, with residual disease, difficulty ambulating and pain.ConclusionsGCE of filum terminale may have an atypical clinical and radiological presentation, albeit with invasive characteristics and anaplasia on histologic analysis. However, its biological behavior is indolent and associated to longer survival. Due to the presence of giant cells, the differential diagnosis of other primary neoplasias at that site were considered, including paraganglioma, malignant peripheral nerve sheath tumors as well as metastatic malignant melanoma, adrenal carcinoma, thyroid gland carcinoma and urothelial carcinoma, that may all harbor giant cells.

Objective Mediastinal schwannomas are sometimes confused with other neoplasms during initial radiological studies, especially when there is a history of cancer in another area. In these cases, a more accurate analysis using computed tomography (CT) or even magnetic resonance (MRI) is required. Our study aimed to perform a retrospective analysis of the clinical and imaging features for a series of patients with mediastinal schwannomas that were confirmed by histology and immunohistochemistry. Results We found eight patients, five men and three women, with an average age of 51 years for this study. The main signs and symptoms at diagnosis were chest pain, dyspnea, cough, and dysphagia. CT showed that the tumor was located in the posterior compartment of the chest in 7/8 cases. Tumors > 10 cm were more heterogeneous and showed cystic changes. All patients underwent posterolateral thoracotomy, and radiological follow-up showed no evidence of recurrence. Histological analysis was considered the gold standard to confirm diagnosis, along with at least one neurogenic IHC marker. In conclusion, mediastinal schwannomas are benign encapsulated tumors. According to CT, schwannomas > 10 cm show cystic degeneration more frequently. Posterolateral thoracotomy allows complete resection and is considered the surgical approach of choice.

Objective: Mediastinal schwannomas sometimes can be confused with other neoplasms in the initial radiological studies, especially when there is a history of cancer in another site and that require a more accurate analysis by computed tomography (CT) or even magnetic resonance (MRI). Our study was aimed to perform a retrospective analysis of the clinical and imaging features in a series of patients with mediastinal schwannomas that were confirmed by histology and immunohistochemistry.Results: We found eight patients, five man and three women with an average age of 51 years. The main signs and symptoms at time of diagnosis were chest pain, dyspnea, cough and dysphagia. CT showed that the tumor was located in the posterior compartment of the chest in 7/8 cases. Tumors >10 cm were more heterogeneous and showed cystic changes. All cases underwent posterolateral thoracotomy and radiological follow-up showed no evidence of recurrence. Histological analysis was the gold standard to confirm diagnosis in addition to at least one neurogenic IHC marker. In conclusion, mediastinal schwannomas are benign encapsulated tumors. By CT, schwannomas >10 cm showed cystic degeneration more frequently. Posterolateral thoracotomy allows complete resection and is considered the surgical approach of choice.

Human Papillomavirus-related multiphenotypic sinonasal carcinoma is a rare, and recently described neoplasm, defined by its association with high-risk Human Papillomavirus, which exclusively affects the sinonasal tract and simulates salivary gland tumors. Due to the infrequency of this neoplasm and the lack of knowledge of its pathological characteristics, it is susceptible to diagnostic error. We describe the clinicalradiological findings of a 54-year-old man with multiphenotypic sinonasal carcinoma related to Human Papillomavirus genotype 56. The diagnosis of multiphenotypic sinonasal carcinoma was suspected by light microscopy and was corroborated by immunohistochemistry and polymerase chain reaction (PCR) analysis. The patient was subsequently treated with 63.6 gray radiotherapies. He is currently alive after a follow-up of 20 months, with a recurrence of the disease. In conclusion, multiphenotypic sinonasal carcinoma is an unusual neoplasm, which is not well recognized and can be confused with adenoid cystic carcinoma. However, multiphenotypic sinonasal carcinoma should be included in the differential diagnosis as we encounter sinonasal tumors, which by histology present tubular, cribriform, and solid growth patterns, accompanied by dysplasia or carcinoma in situ in the superficial mucosa. In this case, it is necessary to perform immunohistochemistry for p16INK4A or PCR to confirm the presence of high-risk Human Papilloma Virus, which would confirm the diagnosis.