1/129. A case of laryngeal neurinoma with neurofibromatosis 2.We present a case of a laryngeal neurinoma in a patient with neurofibromatosis 2. A 39-year-old man presented to our hospital with multiple complaints including progressive bilateral hearing loss, dizziness, dyspnea, dysphagia, and a 9-year history of right lower leg weakness. magnetic resonance imaging demonstrated multiple lesions including bilateral cerebellopontine angle tumors, a foremen magnum tumor, multiple tumors of the spinal cord, a laryngeal tumor, and several retrocervical tumors. Fiberoptic laryngoscopy revealed a large submucosal supraglottic tumor. The laryngeal tumor was visualized through microlaryngoscopy and excised with a KTP laser directed through a quartz fiber.- - - - - - - - - - ranking = 1keywords = mucosa (Clic here for more details about this article) |
2/129. Schwannoma with features mimicking neuroblastoma: report of two cases with immunohistochemical and ultrastructural findings.OBJECTIVE: A study of two cases of a rare variant of benign schwannoma showing areas mimicking neuroblastoma/peripheral primitive neuroectodermal tumour (PNET). methods: Sections of formalin fixed, paraffin embedded specimens were studied by tinctorial stains and immunohistochemistry, and the tissue retrieved from formalin was examined by electronmicroscopy in one case. RESULTS: The tumours were small and subcutaneous. Both showed features of benign schwannoma; one had a multinodular plexiform pattern. In addition, rosette-like structures consisting of collagenous cores surrounded by small round cells or slightly larger epithelioid cells were present. Tumour cells were positive for S100 protein, Leu7, and in one case GFAP, but were negative for neurofilament protein, synaptophysin, and MIC2. Type IV collagen surrounded individual cells. Electronmicroscopy in case 2 confirmed schwannian features (lamina, processes) and failed to show features of neuroblastoma (neuroendocrine granules). CONCLUSIONS: Benign schwannomas may contain rosette-like structures mimicking neuroblastoma/PNET. The techniques used confirmed schwannian differentiation only and eliminated neuroblastoma/PNET. These uncommon variants should be recognised by practising histopathologists to avoid erroneous diagnoses and inappropriate treatment.- - - - - - - - - - ranking = 10.750635669297keywords = lamina (Clic here for more details about this article) |
3/129. Solitary schwannoma of the tympanic membrane: a case report.The external ear canal may be occluded by a rare tumor of the tympanic membrane. We reported herein a case of solid schwannoma arising from the tympanic membrane of a 29-year-old man. It presented as a circumscribed and encapsulated tumor of the external ear canal. The definite diagnosis was based on a careful microscopic examination and pathological findings. A precise excision of the tumor together with part of the tympanic membrane, followed by a myringoplasty was performed. To the best of our knowledge, our case should be the first reported case of this entity in the world literature.- - - - - - - - - - ranking = 3.3367638549218keywords = membrane (Clic here for more details about this article) |
4/129. Malignant peripheral nerve sheath tumor with perineurial cell differentiation (malignant perineurioma).A unique case of malignant peripheral nerve sheath tumor (MPNST) with perineurial cell differentiation occurring in a 63-year-old woman in a subcutis of the forearm is described. The tumor contained cellular and myxoid areas. The neoplastic cells were fusiform with distinct cell borders. They were arranged in storiform pattern and in wavy parallel cell cords in the cellular areas. Focally, a pleomorphism and mitotic activity (including atypical mitoses) similar to those of malignant fibrous histiocytoma were seen. The myxoid parts contained haphazardly oriented cells and scarce lipoblast-like multivacuolated cells mimicking a liposarcoma. In the differential diagnosis, myxoid liposarcoma, dermatofibrosarcoma protuberans, malignant fibrous histiocytoma and low-grade fibromyxoid sarcoma were considered. Immunohistochemically, perineurial differentiation was indicated by the diffuse expression of epithelial membrane antigen and focal reactivity for CD34. The tumor was negative with antibodies to S-100 protein, Leu-7, CD68 (KP1), vimentin and cytokeratin AE1/AE3. Ultrastructure of tumor cells revealed features of MPNST. No recurrence occurred in the patient during 2 years follow up.- - - - - - - - - - ranking = 0.47668055070312keywords = membrane (Clic here for more details about this article) |
5/129. Primary pulmonary neurilemoma. Report of a case with ultrastructural examination.The electron microscopic features of a primary neurilemoma of the lung, a very rare neoplasm, were studied. Characteristic schwann cells were present, with cytoplasm and elongated cytoplasmic processes coated with a basal lamina. The highly characteristic Luse bodies were also seen. We add electron microscopic corroboration to the previous tissue culture confirmation of this unusual benign pulmonary neoplasm.- - - - - - - - - - ranking = 10.750635669297keywords = lamina (Clic here for more details about this article) |
6/129. A migrated lumbar disc herniation simulating a dumbbell tumor.We report a case of a migrated lumbar disc hemiation, which on magnetic resonance imaging (MRI) simulated a dumbbell tumor in a 44-year-old woman who had severe pain in her right buttock and leg. A large epidural mass mimicking a dumbbell tumor was detected at the L5 vertebral level by MRI and computed tomography over myelography. Surgical fenestration of the L4/L5 interlaminar space revealed a dorsolateral epidural mass connected to the L5/S1 intervertebral disc extending laterally through the right L5/S1 intervertebral foramen. Histologically, it was degenerative disc material without active inflammation. Reevaluation of the MRI suggested some clues that might be useful in differentiating such a herniated disc from an epidural tumor.- - - - - - - - - - ranking = 10.750635669297keywords = lamina (Clic here for more details about this article) |
7/129. Diffuse schwannoma involving the entire large bowel with huge extramural development: report of a case.Schwannoma of the large bowel is a rare clinical entity, which has reportedly been recognized to arise from one place with a submucosal tumor morphology. We present herein the unique case of a 25-year-old woman who suffered from a schwannoma diffusely involving the entire large intestine. The patient complained of abdominal distension and imaging studies revealed a giant tumor occupying the whole abdomen, but no confirmed preoperative diagnosis could be made. A laparotomy proved the huge tumor detected preoperatively to be the markedly wall-thickened entire large bowel itself due to the diffuse extramural development of a neoplasm, but no other organs were involved. biopsy specimens from the tumor were histologically diagnosed as benign schwannoma. However, because of the possibility of malignancy, we later performed a total proctocolectomy followed by an ileal J-pouch-anal canal anastomosis. The final pathological diagnosis was also that of a benign schwannoma originating from the large intestine. The patient remains well without recurrence 15 months after surgery. To the best of our knowledge, no such case of a schwannoma in the entire large bowel has yet been reported in the literature, and the pathogenesis of its occurrence remains unknown.- - - - - - - - - - ranking = 1keywords = mucosa (Clic here for more details about this article) |
8/129. neurilemmoma of the mandible.Intraosseous neurilemmoma is rare, representing less than 1% of benign primary bone tumors. The site most commonly involved is the mandible. We report on a neurilemmoma of the mandible in a 30-year-old woman. A panoramic radiograph of the mandible showed a well-defined unilocular osteolytic lesion with a thin uniform sclerotic margin located in the body of the mandible. The CT scan confirmed a well-defined osteolytic lesion with thinning of the cortex of the body of the left side of the mandible. Histologically, the lesion was a moderately cellular neoplasm with distinct palisading and numerous Verocay bodies. Ultrastructurally, the cytoplasmic membranes were distinct and coated by amorphous bands of basal lamina. Complete excision was achieved by removing the tumor from the inferior alveolar nerve.- - - - - - - - - - ranking = 11.22731622keywords = lamina, membrane (Clic here for more details about this article) |
9/129. Benign schwannoma of the esophagus removed by enucleation: report of a case.A submucosal tumor of the esophagus was enucleated by a thoracotomy. A microscopic examination showed the tumor to be composed of spindle-shaped cells showing mild nuclear atypia with vague nuclear palisading and scarce mitotic figures. The tumor was surrounded by peripheral lymphoid cuffs. An immunohistochemical study demonstrated diffuse positive staining for S-100 protein in the tumor cells. The lesion was diagnosed to be an esophageal schwannoma based on these pathological features. Benign schwannoma of the esophagus has been described in five cases in four reports in the English literature. This is the sixth case diagnosed by immunohistochemical studies.- - - - - - - - - - ranking = 1keywords = mucosa (Clic here for more details about this article) |
10/129. Choroidal schwannoma: immunohistochemical and electron-microscopic study.Schwannoma (neurilemoma) arising from the ciliary body and choroid is a rare form of intraocular tumor and usually misdiagnosed clinically as amelanotic melanoma. This case report describes a 73-year-old woman who developed a large nonpigmented intraocular tumor of the choroid in the left eye and underwent enucleation with a clinical diagnosis of malignant melanoma. The tumor consisted of spindle-shaped cells with an indefinite cytoplasm and twisted nuclei, which had positive immunoreactivity for S-100 protein, vimentin, glial fibrillary acidic protein and neural cell adhesion molecule. A continuous basal lamina encompassing the tumor cells was demonstrated by immunostaining for laminin and type IV collagen. Ultrastructurally, tumor cells with scant organelles had delicate cytoplasmic processes apposing each other, all indicative of Schwann cell origin. In reexamination of fluorescein angiograms, ultrasonograms and magnetic resonance images, no findings were incompatible with a diagnosis of choroidal melanoma. Histopathological studies showed that the tumor was a schwannoma. At present, we do not have a benchmark for the clinical diagnosis of intraocular schwannoma.- - - - - - - - - - ranking = 10.750635669297keywords = lamina (Clic here for more details about this article) |
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