1/32. Benign schwannoma of the digestive tract: a clinicopathologic and immunohistochemical study of five cases, including a case of esophageal tumor.We report five cases of schwannomas of the digestive tract. The patients were two men and three women, whose ages ranged from 56 to 74 years. Three cases arose in the stomach, one in the ascending colon, and one in the esophagus; the latter was a hitherto unreported location for this tumor. The schwannomas ranged from 2 to 11 cm in diameter. They were well circumscribed but not encapsulated, with interlacing bundles of spindle cells, nuclear atypia and no mitosis, interspersed with collagenous strands. Inflammatory cells were scattered throughout the tumors and a peripheral cuff of lymphoid aggregates was observed in all cases. Intracellular periodic acid-Schiff (PAS)-positive crystalloids were found in three cases; no skeinoid fibers were seen. A diffuse and intense positivity for vimentin and S-100 protein was detected in all five cases together with a variable and sometimes focal positivity for glial fibrillary acidic protein and neuron-specific enolase. None of the tumors showed expression of CD34 or the smooth muscle antigens tested. The four cases with a sufficient follow-up had a favorable outcome without any recurrence or metastasis. The morphologic and immunohistochemical features of digestive schwannomas were compared with those of other gastrointestinal stromal tumors. Schwannomas have many differences. Digestive schwannomas can be readily recognized on histologic and immunohistochemical examination. They are spindle cell tumors without epithelioid features, with a peripheral cuff of lymphoid tissue. Specific intracellular needle-shaped PAS-positive crystalloids are found in some cases, whereas skeinoid fibers are not. These tumors always express S-100 protein in a diffuse and strong manner, and they express glial fibrillary acidic protein but not express CD34. Digestive schwannomas usually are gastric tumors and have never been reported in the small bowel. They pursue a benign course and are far rarer than gastrointestinal autonomic nerve tumors.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
2/32. 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 = 1keywords = antigen (Clic here for more details about this article) |
3/32. Schwannoma in the sigmoid colon: report of a case.Schwann cell tumor occurring in the intestines is rare. A 68-year-old female came to our hospital because of hematemesis. barium enema and colonoscopic examination revealed submucosal tumor in the sigmoid colon. Laboratory data showed mild anemia. No other abnormal finding was found in the blood chemistry. Tumor marker levels of carcinoembryonic antigen (CEA), CA19-9, alpha feto protein (AFP) and neuron specific enolase (NSE) were within normal limits. The exploratory laparotomy confirmed a large sigmoid colon tumor. She received sigmoid colectomy. The resected specimen was a submucosal tumor with central depression, measuring 4.7 x 3.5 x 3.0 cm in size. The cut surface of the tumor was yellowish hue with necrosis. Histological examination showed spindle-shaped tumor cells with palisading comma-shaped nuclei and the nuclear pleomorphism. Immunohistochemical examination revealed that the tumor was positive for S-100 protein staining, and negative for Actin and for H.H.F. staining. These findings showed that this tumor was of Schwann cell origin. We report here the case in detail of a schwannoma in the sigmoid colon.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
4/32. Subcutaneous malignant epithelioid schwannoma with cartilaginous differentiation.BACKGROUND: Malignant epithelioid schwannoma is a rare tumor. The aim of this study is to describe a case of subcutaneous malignant epithelioid schwannoma with cartilaginous differentiation. methods: Histological, immunohistochemical, and ultrastructural examinations were performed on a tumor that arose on the back of a 37-year-old woman. RESULTS: Histologically, the tumor predominantly consisted of small, round or polygonal cells arranged in cords or nests. Immunohistochemical study revealed that the tumors cells were positive for vimentin, S-100 protein, glial fibrillary acidic protein and neuron specific enolase. The cells were negative for HMB-45, keratin, epithelial membrane antigen, and CAM5.2. Electron microscopic study showed closely associated cells with undifferentiated features. The cells were devoid of external laminae and cellular junctions. CONCLUSION: Malignant epithelioid schwannoma should be pathologically differentiated from other epithelioid tumors with cartilaginous elements.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
5/32. Benign glandular schwannoma.Glandular schwannoma is a rare variant of schwannoma characterized by the presence of glands in an otherwise typical schwannoma. We report a patient with benign glandular schwannoma occurring on the scalp, a site not previously reported. Histologically, a well-defined, encapsulated oval nodule was observed in the subcutaneous tissue. The nodule was composed of a spindle cell component and glandular structures. The spindle cell component stained positively for S-100 protein. All of the glandular epithelium stained with CAM 5.2 and epithelial membrane antigen but not with S-100 protein. The glandular epithelium was focally positive for carcinoembryonic antigen. The histogenesis of the glandular elements in these tumours is still debated. The variable size of the glandular structures in our case was evidence against an entrapped normal sweat gland origin. The glandular epithelium did not stain with S-100 protein at all, but stained with CAM 5.2, which did not support a direct metaplastic origin of the epithelial elements from the schwannian component. A few scattered CAM 5.2-positive cells and microglandular structures in our case may be the initial differentiating epithelial elements possibly derived from pluripotential neural crest cells.- - - - - - - - - - ranking = 2keywords = antigen (Clic here for more details about this article) |
6/32. Cystic schwannoma of the maxillary sinus.OBJECTIVE: Although 25-45% of all schwannomas are reported to occur in the head and neck region, nasal cavity and paranasal sinus involvement is rare, with 32 such cases described till 1999. Of these cases, only three were cystic. Herein we present a cystic schwannoma of the maxillary sinus of a 66-year-old, otherwise healthy male patient. methods: The tumor tissue was routinely processed, embedded in paraffin, and stained with H&E. Immunostaining was performed for S-100 protein, epithelial membrane antigen (EMA) and cytokeratin. RESULTS: A mass with sudden enlargement, inhomogeneous enhancement with cystic areas, S-100 positive membrane-like structures lining the cystic cavity of an otherwise classical schwannoma were the main features encountered in our case. CONCLUSION: We recommend that cystic schwannoma should be kept in mind in the differential diagnosis of cystic masses of the maxilla.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
7/32. Pituicytomas, a mis-diagnosed benign tumor of the neurohypophysis: report of three cases.Pituicytoma is a rare benign primary tumor of the neurohypophysis, occurring in the sellar and suprasellar spaces. We report here three new cases with immunohistochemical and electron microscopic study. Particular attention was paid to the expression of some cell adhesion molecules. These tumors were characterized by bundles of elongated cells strongly immunoreactive to anti-vimentin, S-100 protein, neural cell adhesion molecule and neuron-specific enolase antibodies. glial fibrillary acidic protein (GFAP) was not recorded. It expressed the very late antigen alpha2 (VLAalpha2), but not VLAalpha5, and lacked epithelial markers expression (epithelial membrane antigen, E-cadherin), and specific neuronal markers (synaptophysin, chromogranin, neurofilament). Staining for pituitary hormones was negative. At the ultrastructural level, tumor/blood vessel basal lamina and cytoplasmic intermediate filaments were observed but desmosome or pericellular basal lamina were lacking. In one case few secretory granules were recorded. Differential diagnoses include granular cell tumors, pilocytic astrocytomas and spindle cell tumors such as solitary fibrous tumors, fibroblastic meningiomas and schwannomas. However, the unique pattern of antigenic expression and ultrastructural features of pituicytomas distinguish this rare tumor. As a subpopulation of pituicytes (which are distinctive glial cells of the neurophypophysis), some pituicytomas do not expressed GFAP. This suggests that pituicytomas presumably arise from pituicytes at various stages of their differentiation.- - - - - - - - - - ranking = 3keywords = antigen (Clic here for more details about this article) |
8/32. Schwannoma of a seminal vesicle.We present the first reported case of a schwannoma of the seminal vesicle that occurred in a 48-year-old man who presented with right lower quadrant abdominal pain. Computed tomography scan and magnetic resonance imaging revealed a mass in the patient's right seminal vesicle. The patient was also found to have a rising prostate-specific antigen level and underwent a transrectal ultrasound-guided biopsy of the prostate and seminal vesicles, which revealed prostate cancer and schwannoma of the seminal vesicle, respectively. Radical prostatectomy with en bloc removal of the seminal vesicle mass was performed and the patient has been free of disease 24 months postoperatively.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
9/32. A case of perineurioma with prominent myxoid changes.A perineurioma with prominent myxoid changes is presented. The patient, a 41 year-old woman, presented with a small skin nodule on her back. light microscopy revealed subtle cellular whorls within a myxoid background. immunohistochemistry showed epithelial membrane antigen positivity. In contrast, S-100 protein, common leukocyte antigen, vimentin and AE1-AE3 cytokeratin were negative.- - - - - - - - - - ranking = 2keywords = antigen (Clic here for more details about this article) |
10/32. Schwannoma of the sinonasal tract: a clinicopathologic and immunohistochemical study of 5 cases.CONTEXT: Peripheral nerve sheath tumors are soft tissue neoplasms rarely encountered in the nasal cavity and paranasal sinuses. OBJECTIVE: To describe the clinicopathologic and immunohistochemical features of a series of schwannomas of the sinonasal tract. DESIGN: Surgical pathology files were searched for the diagnosis "sinonasal schwannoma." All histologic documents and clinical data were reviewed. immunohistochemistry was performed on paraffin-embedded tissue with antibodies to S100 protein, epithelial membrane antigen, CD34, and MIB-1. RESULSTS: Five cases of sinonasal schwannoma were retrieved; patients included 3 women and 2 men, aged 20 to 56 years. Three cases were located in the ethmoid sinus. Clinical symptoms were nonspecific (nasal obstruction, epistaxis, and anosmia). All tumors were treated with conservative surgical resection. Pathologic examination showed a spindle cell proliferation without encapsulation in all cases. No cytologic atypia was seen, and the mitotic activity was low (<3 mitotic figures/10 high-power fields). immunohistochemistry showed diffuse positivity with S100 protein and negativity with CD34 and epithelial membrane antigen. MIB-1 staining was low (1%-5% of tumor cell nuclei stained). During the follow-up (median, 6 years), no recurrence or metastasis was observed. CONCLUSIONS: Schwannoma is a very unusual tumor of the sinonasal tract and is associated with nonspecific symptoms. Histologically, sinonasal schwannomas differ from schwannomas of other locations by their lack of a peripheral capsule and possible ulceration of the epithelial covering. Sinonasal schwannomas are treated with conservative surgical resection and have an excellent prognosis.- - - - - - - - - - ranking = 2keywords = antigen (Clic here for more details about this article) |
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