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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Atypical fibroxanthoma is a superficial variant of pleomorphic malignant fibrous histiocytoma. Histopathologically, it is characterized by a dermal nodule composed of bizarre cells arranged in a haphazard-to-fascicular pattern. These cells are spindle or rounded, pleomorphic and with numerous atypical mitotic figures. Some cells appear polygonal with ample and foamy cytoplasm. We recently encountered two elderly patients with atypical fibroxanthoma on their face. Histopathologically, one of the lesions was composed, almost entirely, of clear cells, whereas in the other one aggregations of clear cells constituted a half of the neoplasm. Atypical multinucleated cells with a Touton-like appearance were present. In addition to clear cells, areas of more conventional atypical spindle cells arranged in fascicles were seen, supporting the diagnosis of atypical fibroxanthoma. PAS staining failed to demonstrate glycogen in neoplastic cells. Immunohistochemistry revealed that neoplastic cells expressed positivity for vimentin, muscle-specific actin, and alpha smooth muscle actin, whereas cytokeratin, S-100 protein, EMA, CEA, and desmin were negative. Ultrastructural studies showed that neoplastic cells contained abundant rough endoplasmic reticulum, mitochondria, and numerous lipid vacuoles within the cytoplasm. Clear-cell atypical fibroxanthoma is a rare variant of atypical fibroxanthoma that should be differentiated from other clear-cell neoplasms of the skin.
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PMID:Clear-cell atypical fibroxanthoma: an uncommon histopathologic variant of atypical fibroxanthoma. 908 54

A case of carcinosarcoma composed of both adenocarcinoma and sarcomatous elements in the non-trigone region of the urinary bladder is presented. The epithelial element was a well to poorly differentiated adenocarcinoma with focal squamous metaplasia. The sarcomatous elements disclosed spindle cell sarcoma with focal epithelioid pattern and myxoid change in the stroma, together with chondrosarcomatous and rhabdomyosarcomatous elements. By immunohistochemical examination, not only the carcinoma element but also the sarcomatous elements showed a positive immunoreaction for cytokeratin (CK), epithelial membrane antigen (EMA) and carcinoembryonic antigen. Some population of sarcomatous elements expressed smooth muscle actin and muscle specific actin (MSA) and a limited portion of epithelioid area showed a positive immunoreaction for desmin, MSA and myoglobin, indicating leiomyosarcomatous and rhabdomyosarcomatous differentiation, respectively. Unexpectedly, tumor cells in the chondrosarcomatous element revealed a simultaneous positivity of CK and EMA as well as S-100 protein. Both epithelial and sarcomatous elements showed an intensive positive immunoreaction for p53 and heat shock protein (HSP) 70. However, HSP27 and HSP60 were detected in most epithelial elements and only in a small number of tumor cells in the sarcomatous area. These findings indicate that sarcomatous elements, including heterologous elements, may derive from epithelial elements with partial or complete loss of epithelial features, and different factors other than p53 and HSP70 may associate with the morphological alteration of carcinoma.
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PMID:Carcinosarcoma of the urinary bladder: expression of epithelial markers and different expression of heat shock proteins between epithelial and sarcomatous elements. 908 35

Sarcomatoid carcinomas (carcinosarcomas) are rare lesions in the gastrointestinal tract, where they are most commonly found in the esophagus. We present the first reported case of a sarcomatoid carcinoma of the ampulla of Vater. The tumor was composed of intermixed carcinomatous (adenocarcinoma plus squamous cell carcinoma) and sarcomatous elements. Cytokeratin immunoreactivity was demonstrated focally in the sarcomatoid component, although in other areas there was positive staining for desmin and smooth muscle actin. The possible histogenesis of such lesions is briefly discussed.
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PMID:Sarcomatoid carcinoma of the ampulla of Vater. 909 87

We studied 18 patients with primary malignant smooth muscle tumors of the lung (7 women and 11 men, 5-76 yr old, with a mean age of 50 yr). Lesions varied from 1.7 to 10 cm in greatest diameter. The tumors were classified as low (4 cases), intermediate (2), or high grade (12). Low-grade lesions were characterized by an orderly proliferation of fascicles of spindle cells that intersected at right angles and showed oval-to-spindle cells with cigar-shaped nuclei, minimal pleomorphism, and low mitotic activity, without hemorrhage or necrosis. Intermediate-grade lesions retained the fascicular configuration but showed increased cellularity with atypia and dense chromatin pattern, occasional pleomorphism, and mild increase in mitotic activity. High-grade lesions showed high cellularity, marked pleomorphism and atypia, frequent areas of hemorrhage and necrosis, and high mitotic activity. Immunohistochemical studies in 16 cases showed positive staining of tumor cells with smooth muscle actin in 12, desmin in 5, and coexpression of actin and/or desmin and keratin in 3. Six patients with low- and intermediate-grade lesions were alive and well from 2 to 12 years after diagnosis (mean follow-up time, 6 yr); 8 with high-grade lesions died of their tumors with widespread metastases from 1 to 24 months after diagnosis (median survival time, 5 mo). One patient whose tumor showed features of high-grade leiomyosarcoma was alive and well 12 years after surgery. Three patients with high-grade tumors were lost to follow-up. Our findings suggest that histologic grade may be the most reliable prognostic parameter for predicting clinical behavior in primary leiomyosarcoma of the lung and that smooth muscle actin is the most sensitive immunohistochemical marker for establishing the diagnosis in these tumors. Primary leiomyosarcoma should be considered in the differential diagnosis of pulmonary spindle cell neoplasms; histologic grading may be of value in the planning of therapy and assessment of prognosis for these lesions.
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PMID:Primary leiomyosarcomas of the lung: a clinicopathologic and immunohistochemical study of 18 cases. 912 17

We report a case of primary solitary fibrous tumor occurring in the intramedullary thoracic spinal cord in a 47-year-old man. The tumor predominately consisted of spindle cells separated by abundant collagen; a few areas of hemangiopericytomatous morphology were also present. The diagnosis was confirmed by immunohistochemistry and electron microscopy. The tumor was reactive to vimentin and CD34 but was negative for glial fibrillary acid protein (GFAP), S-100, smooth muscle actin, epithelial membrane antigen, HMB-45, myelin basic protein, and keratin; ultrastructural examination showed fairly undifferentiated cells within a collagenous matrix, few tight junctions, and sparse extravascular basement membrane. The occurrence of this tumor within the spinal cord parenchyma and in other extraserosal sites emphasizes the current belief that solitary fibrous tumors arise from mesenchymal tissues and are not restricted to the pleura and other serosal surfaces. Furthermore, solitary fibrous tumor is an entity that must be considered in the differential diagnosis of spindle cell central nervous system neoplasms.
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PMID:Solitary fibrous tumor of the spinal cord. 913 Sep 96

Twenty-eight cases of nasopharyngeal angiofibroma were studied immunohistochemically for cytoskeletal phenotyping of stromal cells. Electron microscopy was also used to study the ultrastructure of five of the tumors. All typical stromal cells showed intensive immunostaining for vimentin, but were negative for smooth muscle actin and desmin. Ultrastructurally, most of these cells appeared to be exclusively fibroblasts. However, in some areas stromal cells were seen that morphologically resembled myofibroblasts by their shapes and arrangement, and were characterized by the coexpression of vimentin and smooth muscle actin. Electron microscopy confirmed their myofibroblastic nature. The present study showed that the typical stromal cells in nasopharyngeal angiofibromas were fibroblasts and not myofibroblasts. In these tumors myofibroblasts occurred only focally, in connection with fibrotic areas and exclusively as a vimentin+/actin+cytoskeletal phenotype. This indicates that myofibroblasts are not primary stromal tumor cells in nasopharyngeal angiofibromas, but occur due to regressive changes.
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PMID:Immunohistochemical and electron microscopical characterization of stromal cells in nasopharyngeal angiofibromas. 915 Oct 19

Malignant myoepitheliomas of the breast are rare. We report a case of spindle cell malignant myoepithelioma studied by light microscopy and immunohistochemistry. The malignant myoepithelial cells stained positively for cytokeratins, smooth muscle actin and vimentin, but not for epithelial membrane antigen. The tumor showed a focal positivity for S100 protein. A short review of the morphology and immunohistochemistry of cases reported in the international literature is given in a table. Morphologically malignant myoepitheliomas can be subdivided into spindle cell malignant myoepitheliomas and malignant adenomyoepitheliomas.
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PMID:Malignant myoepithelioma of the breast. Case report with immunohistochemical study. 915 29

Solitary fibrous tumors (SFTs) are rare, spindle-cell neoplasms generally associated with the serosal surface, especially the pleura. Histopathologic, immunohistochemical, ultrastructural, and flow cytometric analyses were performed on seven SFTs of extrapleural sites (two retroperitoneal, two soft tissue, one each peritoneal, nasal cavity, and orbit). Five patients were women, and two were men, aged from 21 to 68 years (average, 39 yr). All of the lesions presented as well-circumscribed masses. The lesions ranged in size from 2 to 20 cm in greatest diameter. Histologically, these lesions were entirely comparable to the pleural SFTs and lacked the characteristic features of other recognized neoplasms that occur in these regions. One tumor contained pleomorphic and round-cell sarcomatous foci. Immunohistochemically, all of the tumors were strongly positive for vimentin and CD34. Six of the seven tumors showed varying numbers of spindle cells positive for alpha smooth muscle actin, HHF35, neuron-specific enolase, Leu 7, or glial fibrillary acidic protein. Ultrastructural examinations of three tumors showed that they were composed of primitive mesenchymal or fibroblast-like cells. Six tumors examined were diploid by flow cytometric examination. Clinical follow-up in six patients ranged from 1 to 7.5 years (average, 2.6 yr) and showed that five patients remained well with no evidence of disease after excision and that the patient with the sarcomatous elements died of recurrence 2.5 years after surgical treatment. These findings suggest that SFTs represent ubiquitous neoplasms of fibroblasts or primitive mesenchymal cells with aggressive potential.
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PMID:Extrapleural solitary fibrous tumor: a report of seven cases. 916 Mar 8

Spindle epithelial tumor with thymus-like differentiation (SETTLE) is a rare and distinctive low-grade neoplasm of thymic or related branchial pouch differentiation. The tumor usually presents in the thyroid or lateral neck of children and adolescents and could mimic spindle-cell carcinoma, synovial sarcoma, or malignant teratoma. We report the clinical, cytologic, histologic, immunohistochemical, and ultrastructural features of a SETTLE present for 10 years in a 15-year-old boy. The fine-needle aspirate, initially interpreted as synovial sarcoma, contained numerous clusters of bland spindle cells, with a few detached sheets of columnar mucous cells in a homogeneous background of dissociated spindle cells. Mitoses, necrosis, and atypia were not present. The excised tumor was a well-circumscribed, white-tan mass, with occasional microcysts. Microscopically, the mass consisted of a lobulated, highly cellular, spindle-cell neoplasm arranged in intersecting, whorled, and storiform fascicles separated by fibrous bands. Entrapped within the fibrous bands were squamous-lined cysts and benign-appearing glands lined by columnar epithelium with goblet cells or ciliated pseudostratified epithelium. Immunohistochemically, the spindle cells showed diffuse reactivity for cytokeratins, smooth muscle actin, muscle-specific actin, and MIC-2, and they were negative for epithelial membrane antigen, calcitonin, and thyroglobulin. Ultrastructurally, numerous perinuclear tonofilaments, some aligned with mature desmosomes, were identified in the spindle cells. Occasional cells showed thin filaments with fusiform dense bodies occupying the peripheral cytoplasm. These findings distinguish SETTLE from ectopic thymoma, synovial sarcoma, medullary carcinoma, and teratoma, and they support a thymic epithelial origin for SETTLE, possibly with myoepithelial differentiation.
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PMID:Spindle epithelial tumor with thymus-like differentiation: a case report with cytologic, histologic, immunohistologic, and ultrastructural findings. 916 Mar 19

Central giant cell granulomas (CGCGs) are jaw tumors of unknown origin that often exhibit an aggressive, though unpredictable, clinical course. The purpose of this study was to determine the immunoprofile of the mononuclear cells that seem to be responsible for the biologic behavior of these tumors. Numbers of cells in cell cycle were also determined and compared in clinically aggressive and non-aggressive CGCGs. Sixteen aggressive and 12 non-aggressive CGCGs were immunohistochemically stained with antibodies to CD34, CD68, factor XIIIa, alpha-smooth muscle actin, prolyl 4-hydroxylase, Ki-67, and p53 protein. Cell populations and numbers of cells in cell cycle were determined through microscopic quantitative assessment. CD34-positive cells were limited to support vessels. CD68-positive mononuclear cells constituted a small population of cells in all tumors. With two exceptions, factor XIIIa-positive cells were rarely seen. Alpha-smooth muscle actin staining was present in approximately half the tumors, and occasionally large numbers of positive cells were seen. Most mononuclear cells were positive for fibroblast-associated antigen. No phenotypic differences were detected between aggressive and non-aggressive tumors. P53 protein did not appear to be overexpressed in CGCGs. Ki-67 staining showed that only mononuclear cells were in cell cycle, and that there were no differences between aggressive and non-aggressive tumors. We conclude that CGCGs are primarily fibroblastic (and myofibroblastic) tumors in which macrophages appear to play a secondary role. Tumor cells show no differentiation toward endothelial cells or macrophage-related dendrocytes (factor XIIIa). Cellular phenotypes and numbers of cells in cell cycle are similar in both aggressive and non-aggressive tumors.
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PMID:Central giant cell granulomas of the jaws: phenotype and proliferation-associated markers. 917 89


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