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

The ultrastructural and immunohistochemical findings are reported in two ovarian myxomas, one of which was also associated with a sclerosing stromal tumor of the same ovary. Both neoplasms showed a myxoid, moderately cellular proliferation of spindle and stellate cells interspersed with areas of fibrosis and hemorrhage as well as delicate vascular spaces. Ultrastructurally, stellate neoplastic cells with irregular nuclei and occasional nucleoli were embedded in a mucinous and loose collagen matrix. Their cytoplasm showed abundant intracytoplasmic thin filaments that rarely condensed into poorly formed dense bodies. These thin filaments correlated with immunoreactivity for muscle-specific actin and vimentin. The neoplastic cells showed no immunoreactivity with antibodies to desmin, S-100 protein, cytokeratin AE1:AE3, factor VIII-related protein, or placental alkaline phosphatase. These ultrastructural and immunohistochemical findings are consistent with myofibroblastic differentiation. These ancillary studies exclude important, clinically more aggressive differential considerations such as myxoid rhabdomyosarcoma, myxoid liposarcoma, myxoid neural tumors, mucinous adenocarcinoma showing pseudomyxomatous change, and myxoid-appearing endodermal sinus (yolk sac) tumor.
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PMID:Ovarian myxoma: ultrastructural and immunohistochemical findings. 150 39

The pathological and cytogenetic features of an extrarenal malignant rhabdoid tumor (MRT) arising from the paravertebral region in an infant were investigated. The patient died 4 months after diagnosis, due to aggressive tumor progression. The tumor was composed of medium-sized round cells with cytoplasm containing eosinophilic inclusions, which ultrastructurally were composed of densely packed whorled intermediate filaments. Flow-cytometric analysis of the tumor cells revealed a diploid pattern. Amplification of the N-myc oncogene was not identified. Immunohistologically, the inclusion bodies showed a positive reaction with antiserum against vimentin. The tumor cells were not reactive with antiserum against epithelial membrane antigen, anti-keratin (polyclonal) or cytokeratin (monoclonal, CK1), but did react with 5H10, an antiserum established from human sarcomatous Wilms' tumor. This case is discussed with reference to the literature on extrarenal MRT, placing stress on the histogenesis of this tumor.
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PMID:Cytogenetic characteristics of a malignant rhabdoid tumor arising from the paravertebral region. A case report. 150 7

Merkel cell carcinoma is a rare cutaneous neuroendocrine tumor that occurs predominantly in the head and neck region of older patients. An 88-year-old white man had an erythematous, umbilicated tumor on his lower lip, which on histopathologic examination showed solid sheets of infiltrating basaloid round cells with a high mitotic index. Globular, paranuclear immunostaining for low-molecular-weight cytokeratins (Nos. 8, 18, and 19) and neurofilament was observed. On ultrastructural examination, the tumor cells demonstrated paranuclear whorls of intermediate filament aggregates and occasional electron-dense granules. This unique cytokeratin- and neurofilament-staining pattern with coexpression enabled the Merkel cell carcinoma to be differentiated from other small cell malignant tumors that included metastatic neuroendocrine carcinomas from other regions. The follow-up 1 year after surgery and radiation showed that the patient remained disease free. Review of the literature revealed 11 cases of oral Merkel cell carcinomas with a predilection for the labial mucosa of older men. The mode of treatment and the clinical course of these cases are also presented, with an update on therapeutic management of Merkel cell carcinomas.
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PMID:Merkel cell carcinoma of the labial mucosa. An immunohistochemical and ultrastructural study with a review of the literature on oral Merkel cell carcinomas. 150 28

Six infants with acute megakaryoblastic leukemia and a translocation (1;22)(p13;q13) were studied. There were five female infants and one male infant, and the age at initial examination varied from 0.8 to 6.5 months (median, 2.3 months). All the patients had hepatosplenomegaly and anemia (6 to 8.3 g/dL), and four patients had thrombocytopenia (9,000 to 63,000/mm3). The bone marrow showed prominent fibrosis in five cases and reticulin fibrosis in one patient at presentation. Crush artifact often made the histologic sections difficult to interpret, but typical megakaryoblasts could be identified in the smears. Biopsy specimens of the liver and lymph node were suggestive of a nonhematopoietic malignant condition because of the cohesiveness of the tumor cells, stromal fibrosis, and the prominent sinusoidal and vascular pattern of infiltration. Immunophenotyping of peripheral blood mononuclear cells was helpful in identifying the blasts as belonging to the megakaryoblastic lineage. Using a panel of mononclonal antibodies, it was also possible to confirm the nature of the infiltration in paraffin sections and to differentiate it from other childhood small round cell tumors, especially neuroblastoma in paraffin sections (typical staining pattern: CD45-, CD43+, vW Factor, Ulex europeus I+, CD20-, CD45RO-, synaptophysin-, chromogranin-, cytokeratin-, desmin-). This special type of infantile acute leukemia can be recognized with confidence if one is aware of its clinical features, peculiar pathologic characteristics, the morphologic features and immunophenotype of the megakaryoblasts, and the unique cytogenetic abnormality.
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PMID:Acute megakaryoblastic leukemia in infants with t(1;22)(p13;q13) abnormality. 151 33

Histological examination of a tumor centered in the body of the pancreas of a 65-year-old Iranian man revealed it to have a substantial component in which osteoclast-like giant cells were set within a stroma of pleomorphic mononuclear cells though other areas were composed of conventional adenocarcinoma. Immunocytochemistry was used to investigate the differentiation of the various component cells of the tumor. The carcinoma cells of the usual type expressed epithelial antigens (EMA and cytokeratin). The giant cells expressed vimentin and showed membrane staining with anti-LCA, in common with examples of cells originating from the mononuclear phagocytic system, including normal osteoclasts. The accompanying stromal cells expressed vimentin only. This implies that the giant cells are likely to have their origin in the bone marrow, whereas the mononuclear stromal cells that separate them may represent tumor cells that have lost their epithelial phenotype. The giant cells are therefore an unusual tissue response to the presence of the carcinoma.
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PMID:Adenocarcinoma of the pancreas with osteoclast-like giant cells: a case report with immunocytochemistry. 151 8

We report a case of leiomyomatosis that involved the small intestine and colon. On gross examination, the bowel wall was irregularly thickened at various levels. Histologically, the lesions were characterized by multifocal, diffuse tumor masses that were present in the muscular layers. These masses consisted of proliferating smooth-muscle cells that often surrounded prominent blood vessels. Cytologic atypia was not observed, and the mitotic count was low, illustrating the benign nature of the tumors. Findings from immunohistochemical analysis of the lesions were essentially negative; vimentin, cytokeratin, actin, desmin, and S100 stains showed no reactivity in the tumor cells, despite positive internal controls. By reviewing the literature, we found several reports on related lesions that occurred in the gastrointestinal tract; diffuse leiomyomatosis of the esophagus and the colon have been reported. We did not find any report on the small intestinal variant of the disease; therefore, it seemed useful to term this new localization as leiomyomatosis of the small intestine and colon.
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PMID:Combined leiomyomatosis of the small intestine and colon. 841 66

Three girls, one 14 and two 15 years of age, with the recently described neoplasm that has been designated "intra-abdominal desmoplastic small round cell tumor with divergent differentiation," and ovarian involvement at presentation are described. In two cases the ovarian tumor was initially thought to be the primary neoplasm. In all cases there was extensive extraovarian tumor at the time of presentation. The ovarian involvement was bilateral in two cases and unilateral in the third. Microscopic examination showed prominent nodular growth within the ovaries. The tumors were characterized predominantly by nests of small cells with hyperchromatic nuclei and scant cytoplasm separated by a prominent desmoplastic stroma. A few tubules containing mucinous secretion were present in one case. On immunohistochemical staining many of the tumor cells stained positively for cytokeratin, epithelial membrane antigen, desmin, and vimentin. Staining for neuron-specific enolase was present in two cases but was conspicuous in only one of them. Leu-7 was expressed by the tumor cells in two cases, and S-100 protein by one, giving further support to the possibility of neuroectodermal differentiation within some of these neoplasms. The two cases studied by electron microscopy both showed frequent intercellular junctions, basal lamina, cytoplasmic filaments, and sparse, small dense granules of either neuroendocrine or lysosomal type. Paranuclear aggregates of filaments were found in one case and cellular processes were prominent in the other case. The differential diagnosis in these cases was extensive and included a number of small cell tumors that may involve the ovary, either primarily or secondarily, in young females. The desmoplastic small round cell tumor should be considered in such cases when the appearances on routine examination are consistent with the diagnosis, and appropriate immunohistochemical stains should be performed to confirm the diagnosis.
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PMID:Ovarian involvement by the intra-abdominal desmoplastic small round cell tumor with divergent differentiation: a report of three cases. 156 48

We report a case an adenosquamous carcinoma of the gallbladder that extended to the proximal transverse colon. Metastatic tumor was present in regional lymph nodes and the liver. Microscopically, the tumor was composed of malignant epithelial cells that were cytokeratin-, epithelial membrane antigen-, and carcinoembryonic antigen-positive. The adjacent desmoplastic stroma of the primary tumor, as well as the metastasis, contained giant cells that morphologically resembled osteoclasts. Immunohistochemical studies showed that the giant cells were cytokeratin-, epithelial membrane antigen-, and carcinoembryonic antigen-negative but weakly alpha 1-antichymotrypsin-positive. While tumors containing osteoclast-like giant cells have been described in the breast, lung, liver, and thyroid, this is the first report of a tumor with this morphology originating in the gallbladder. The presence of the giant cells adjacent to both the primary and metastatic tumor and not at any other location suggests that the tumor cells are producing a substance that induces the formation of the nontumoral giant cells.
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PMID:Stromal osteoclast-like giant cells in an adenosquamous carcinoma of the gallbladder. 159 94

The clinicopathological, ultrastructural and immunohistochemical characteristics of four primary tumors of the middle ear are reported. These neoplasms showed a striking, heterogeneous aspect ranging from solid-trabecular (Type I) to tubulo-glandular (Type II) growth patterns. Secretory activity of the tumor cells was evaluated by immunohistochemistry and electron microscopy. Based on these procedures, three cell types were found, mainly limited to tumors with a tubulo-glandular (Type II) growth pattern. Most frequent were B-cells with an abundant pale cytoplasm containing neuroendocrine granules, both cytokeratin and vimentin as well as several endocrine marker substances. Less frequent were A-cells, which are slender, darkly staining and line the glandular lumina. They showed exocrine activity only and stained strongly with a polyclonal cytokeratin antibody. Finally, least frequent were amphicrine cells, which were characterized by both lumina and neuroendocrine granules in their cytoplasm and were interpreted as the link between A and B cells. Although this morphological description closely resembles that of carcinoids and adenocarcinoids of the respiratory tract and gut, the clinical behaviour of these middle ear tumors nevertheless seems different, with no recurrence or metastasis after a follow-up of 1 to 14 years (median 78 months). Therefore, some authors suggest that these tumors should be classified as middle ear adenomas or adenomatous tumors. However, we strongly feel that these tumours represent a distinct entity and can be classified as adenocarcinoids or amphicrine tumors, i.e. demonstrating both exocrine and endocrine activities. Further work is required to evaluate the exact proportion of neuroendocrine and amphicrine tumors in the heterogeneous group of adenomas and in the rarely described group of adenocarcinomas.
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PMID:Adeno-carcinoid or amphicrine tumors of the middle ear a new entity? 159 87

Gliosarcomas are mixed tumors with malignant glial and mesenchymal elements. The number of GFAP-positive tumor cells decreases with the increase of sarcomatous components, until whole areas may be GFAP negative. These distinct differentiations may, however, lead to false interpretations in small tissue samples. In this connection, it is of interest that, according to other reports, glial tumors may be positive for different anti-keratin antibodies and this prompted us to undertake a systematic investigation of the immunoreactivity of gliosarcomas using a panel of well-characterized monoclonal antibodies against cytokeratins (KL1, AE 1/3, Lu-5, CK-19, CK MNF 116 and Ma-903). These cases were further studied with the anti-epithelial non-cytokeratin antibodies EMA, HEA 125, Ber-EP4, CEA as well as the melanoma-antibody HMB-45, Leu-M1, GFAP and vimentin. As screening study we examined 20 cerebral metastatic carcinomas, 21 malignant gliomas (including 6 gliosarcomas) and 3 metastatic melanomas with the monoclonal antibodies KL1 and HMB-45. All cerebral metastatic carcinomas and 4/6 gliosarcomas were positive for KL1, whereas all melanomas, 2 metastatic carcinomas and 3 gliosarcomas showed an immunostaining with HMB-45. All gliosarcomas were positive with at least one of the tested anti-cytokeratin antibodies. The gliosarcomas did not show an immunoreaction in any of the cases when CEA, HEA 125, Ber-EP4, EMA or Leu M1 were applied. In our opinion, the monoclonal antibodies HEA 125 and Ber-EP4 could obviously be helpful in differentiating gliosarcomas from metastatic carcinomas.
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PMID:Epithelial and melanoma antigens in gliosarcoma. An immunohistochemical study. 159 90


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