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

We report an unusual large, multicystic, posterior fossa neuroepithelial neoplasm involving the cerebellum, brain-stem, and quadrigeminal cistern of a 9-month-old girl. The neoplasm consisted of variably sized, sharply demarcated nests of small cells with a high nuclear-cytoplasmic ratio and moderately basophilic nuclei, embedded in a desmoplastic, immature-appearing, mesenchymal stroma. The nests contained mitoses but none were seen in the stroma. Glial fibrillary acidic protein (GFAP), neurofilament protein, synaptophysin, and cytokeratin (AE-1) were expressed in the nests. Mesenchymal cells were negative for neural markers but positive for vimentin and desmin. The neoplasm was interpreted as a mixed mesenchymal and primitive neuroectodermal tumor (PNET) with histologic features reminiscent of a recently described intraabdominal desmoplastic small cell tumor. The tumor responded poorly to chemotherapy and a second operation was performed 1 year later. The second specimen bore no resemblance to the original and consisted of epithelial-like nests and clusters of neoplastic cells frequently interrupted by sinusoidal vessels. Tumor cells had medium-sized vesicular nuclei with small nucleoli, and a granular cytoplasm. Occasional less cellular islands of neuropil-like tissue contained larger cells having eccentric, vesicular nuclei with prominent nucleoli and abundant pink cytoplasm. Mitoses were not conspicuous. Many cells expressed synaptophysin, neurofilament protein, and GFAP. Neurofilament protein was strongly positive in the larger, neuron-like cells and synaptophysin stained the neuropil-like areas strongly but was less prominent in the neuronal perikarya. Unexpectedly, the neuropil-like areas expressed epithelial membrane antigen, whereas the neuronal cells were negative for chromogranin A. The peculiar histologic picture, combination of phenotypic markers, and remarkable biologic behavior of this unusual tumor defies classification according to existing nomenclature and exemplifies the broad range of phenotypes expressed by primitive neuro-epithelial neoplasms.
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PMID:Desmoplastic primitive neuroectodermal tumor with divergent differentiation. Broadening the spectrum of desmoplastic infantile neuroepithelial tumors. 138 73

Six cases of extracranial meningioma (EM) are reported. In addition to the routine paraffin section and HE stain as examined by light microscope, immuno-histochemical studies with antibodies against vimentin, EMA, CK1, and S-100 were done. One specimen was examined by electron microscopy as well. For subdivision, 4 belonged to meningotheliomatous type and each of the rest belonged to transitional and psammomatous types respectively. According to Lopez's classification, 5 were Type II and 1 was Type III. The significance of Lopez's classification of this tumor in clinical diagnosis and differential diagnosis, in histogenesis and pathogenesis are discussed.
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PMID:[Extracranial meningioma--a report of 6 cases]. 139 78

We report a previously undescribed virilizing malignant adrenocortical tumor in an 21-month-old infant with elevated serum alphafetoprotein. The tumor consists of a peculiar mixture of immature epithelial and mesenchymal elements as well as slit-like spaces partially lined by primitive epithelial cells. Focally, the tumor has features reminiscent of the normal embryologic development of the adrenal cortex. A panel of immunohistochemical stains revealed only vimentin reactivity. We propose the term "adrenocortical blastoma" for this unusual neoplasm.
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PMID:Adrenocortical blastoma. 139 49

Tumor-cell interaction with the vessel wall during metastasis involves adhesion, induction of endothelial-cell retraction and spreading on the exposed sub-endothelial matrix. The signals for initiation of tumor-cell spreading and the receptors involved are unknown. A protocol was developed to distinguish between initial tumor-cell (B16 amelanotic melanoma; B16a) adhesion to and spreading on fibronectin. The time for maximum spreading was 50 min. Treatment with a lipoxygenase metabolite of arachidonic acid [12(S)-HETE] resulted in maximum spreading in 15 min (max. effect approx. 0.1 microM). Other lipoxygenase metabolites were ineffective. 12(S)-HETE treatment induced a rearrangement of F-actin, vinculin, vimentin intermediate filaments and integrin alpha IIb beta 3, but not integrin alpha 5 beta 1. Antibodies to alpha IIb beta 3 but not alpha 5 beta 1 blocked the 12(S)-HETE effect on B16a spreading. B16a-cell attachment to fibronectin resulted in increased metabolism of arachidonic acid to 12(S)-HETE, which was inhibited by lipoxygenase but not by cyclo-oxygenase inhibitors. Accordingly, lipoxygenase inhibitors but not cyclo-oxygenase inhibitors blocked spontaneous B16a-cell spreading. The protein-kinase-C inhibitors calphostin C, H7 and staurosporine also inhibited spreading, while the protein-kinase-A inhibitor H8 was ineffective. These data suggest that B16a-cell spreading on fibronectin is initiated by a lipoxygenase metabolite [12(S)-HETE] of arachidonic acid and is mediated by protein kinase C.
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PMID:The lipoxygenase metabolite 12(S)-HETE promotes alpha IIb beta 3 integrin-mediated tumor-cell spreading on fibronectin. 139 43

An operable case of pedunculated localized mesothelioma of the pleura, a 62-year-old male, came to our clinic with chief complaint of chest X-ray abnormal shadow. On suspicion of pleural tumor, resection was performed. The operative findings revealed that the tumor was arising from visceral pleura of S1 + 2 a segment of left upper lobe, and didn't invade into peripheral tissue. The microscopic findings revealed that the tumor was consist of spindle tumor cells and capillary-like lesions, and had high cellularity and many mitosis. The tumor was diagnosed as localized malignant mesothelioma. Immunohistochemical stainings were performed using six monoclonal antibodies, vimentin, CEA, EMA, keratin (AE1, AE3), Leu-M1. Only vimentin reacted with tumor cells.
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PMID:[An operated case of malignant localized mesothelioma of the pleura]. 140 76

Peritoneal mesotheliomas are uncommon among cows although there has been an increase in the frequency of diagnosis of this neoplasia in the past few years. The case of a 2 year old cow is described. On post-mortem examination, several nodules of variable size were found in the peritoneal cavity. These nodules fused together, but they did not go deep into the organs. Histologically, such nodules were formed by a population of fusiform cells of malignant morphological character and sarcomatous appearance. Immunocytochemical study, using P.A.P. techniques, showed a highly positive reaction towards vimentin and a negative reaction towards wide-spectrum cytokeratins, hence suggesting a mesenchymal origin of the neoplasia. According to the histopathological study, a multifocal peritoneal mesothelioma of sarcomatous appearance was identified.
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PMID:Immunocytochemical identification of a bovine peritoneal mesothelioma. 141 92

We analyzed 46 gastrointestinal stromal tumors (GISTs) using a panel of antibodies to determine the frequency of smooth muscle differentiation and the relationship of immunophenotype to histopathologic features and clinical behavior. Thirty-six GISTs were classified as benign or malignant based exclusively on clinical behavior; a 2-year minimum follow-up was required for benign lesions. GISTs were immunopositive in the following categories: vimentin 45 of 46, desmin nine of 45, muscle-specific actin (MSA) 36 of 46, alpha-smooth muscle actin (SMA) 34 of 46, chicken gizzard actin-7 zero of 38, cytokeratin two of 46, S100 protein six of 46, glial fibrillary acidic protein (GFAP) zero of 46, synaptophysin zero of 46, and chromogranin one of 46. At least one muscle marker was positive in 39 of 46 tumors. Five GISTs were MSA positive/SMA negative, and three were MSA negative/SMA positive. All desmin-positive cases reacted with MSA or SMA. Eight GISTs were positive for vimentin, MSA, SMA, and desmin, whereas seven were vimentin positive only. Compared with the latter, the former tended to be smaller, less often necrotic, and clinically benign (p less than 0.05 for each). All vimentin-positive only GISTs were malignant. Immunohistochemical features did not correlate with tumor site, cellularity, nuclear pleomorphism, or mitotic rate. Benign GISTs were less cellular than were malignant GISTs (p less than 0.05), but they did not differ statistically in degree of nuclear pleomorphism, necrosis, mitotic rate, or size. We conclude that (a) 85% of GISTs react with at least one muscle antibody; (b) immunohistochemical features are unrelated to anatomic site; (c) SMA is, in effect, as sensitive as MSA, whereas desmin is less sensitive; and (d) simultaneous vimentin, MSA, SMA, and desmin positivity correlates with a benign outcome.
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PMID:Muscle differentiation and clinicopathologic features of gastrointestinal stromal tumors. 141 3

Inflammatory pseudotumor is a pathologic term used to describe reactive, pseudoneoplastic phenomena, which reportedly occur in many parts of the body. Clinicopathologic and immunohistochemical findings in six cases of inflammatory pseudotumor of the major salivary glands are described. All six lesions involved the parotid gland. There were three men and three women affected, with a median age of 72.5 years. All patients presented with a swelling of several months' duration in the parotid region. Five patients were alive and free of tumor at an average of 3.2 years after surgical removal, and one patient was lost to follow-up. The lesions were firm, discrete nodules, grossly described as homogenous yellow-gray tissue. Histologically, all lesions contained a diversified admixture of four histological elements: (a) myofibroblasts, (b) histiocytes, (c) plasma cells, and (d) lymphocytes. Results of immunohistochemical studies showed a biphasic spindle cell population of myofibroblasts and histiocytes with variable staining characteristics for KP-1(CD-3), smooth muscle actin, muscle-specific actin, and vimentin. These findings are in agreement with the concept that inflammatory pseudotumor is a fibroinflammatory lesion with an abundant component of myofibroblastic/fibrohistiocytic elements.
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PMID:Inflammatory pseudotumors of the major salivary glands. Clinicopathologic and immunohistochemical analysis of six cases. 141 8

Reported in this paper are two cases of aggressive perineovulvar angiomyxoma. Soft, painless tumours with gelatinous cut surface were detected in either patient, two women aged 32 and 46 years. Histological findings included fibromyxoid stroma with spindle-shaped and stellate cells as well as vascularization in striking abundance. Most of the vessels were thin-walled. There was no plexiform arborization. Strongly atypical nuclei or mitoses or necrotic foci were not recordable. The tumour exhibited infiltrative growth. Tumour cells could be immunohistochemically associated with antibodies against vimentin, whereas negative responses were recorded from antibodies against S-100 protein, factor-VIII-associated protein and pancytokeratin. Aggressive angiomyxoma is a biologically benign neoplasia prone to recurrence and typically localized in soft tissue of the pelvic region. Metastases so far have never been found. Wide local excision has proved to be the optional therapeutic approach.
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PMID:[Aggressive angiomyxoma of the vulva and perineum]. 142 Jan 11

Progressive unilateral sensorineural deafness and tinnitus developed in a 59-year-old woman over a 1-year period. Clinical examination showed a tumor mass which almost completely filled the tympanic cavity, and grew around the auditory ossicular chain. Histological findings revealed the tumor to be a primary carcinoid of the middle ear. Neuro-endocrine differentiation was confirmed immunohistochemically by positivity for neuron-specific enolase, chromogranin, pancreatic polypeptide and synaptophysin. Using electron microscopy, neuroendocrine granules could be visualized. In addition, both light and electron microscopy revealed that cells had an epithelial differentiation with mucin granules while immunohistochemistry showed a positivity for cytokeratins. The detection of intermediary filaments (immunohistochemically with vimentin and under electron microscopy) was unique to this neoplasm and has to be considered in distinguishing the carcinoid tumor from the papillary adenoma of the middle ear. Tumor prognosis is excellent with radical extirpation from the middle ear. In the case presented, there has been no evidence for either recurrence or metastases 10 months after surgical resection.
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PMID:[Carcinoid of the middle ear: a rare tumor with biphasic differentiation. Case report with special reference to immunohistochemistry and electron microscopy]. 142 31


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