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

Two decades of research with resorptive neurocarcinogens firmly established the high potency of methyl and ethylnitrosourea (MNU and ENU) as neurocarcinogens, particularly in rats. There are significant differences in susceptibility to these agents among species. There are also differences among age groups. Fetuses are between 50 to 100 times more susceptible than adult rats. One single iv inoculation of 20-50 mg/kg ENU into pregnant rats may produce neurogenic tumors in 100% of the offspring. The tumors produced by these compounds have been well characterized morphologically, biologically, biochemically and histochemically. Tumors produced by both compounds are mostly gliomas and neurinomas (Schwannomas), however, clear differences exist between ENU and MNU produced neoplasms. Transplacental exposure to ENU generally results in a high number of anaplastic neurinomas and mostly differentiated gliomas (astrocytomas, oligodendrogliomas or mixed gliomas). In contrast, multiple exposures of adult rats to MNU result in a moderate number of mostly differentiated neurinomas and a high number of anaplastic gliomas. Tumors usually start out as well differentiated oligodendrogliomas or astrocytomas. As they grow larger, they become more mixed and anaplastic. In contrast to spontaneous gliomas in old rats, MNU and ENU-induced astrocytomas can be readily identified with well established biomarkers such as the S100 protein and particularly GFAP (glial fibrillary acidic protein). Neurinomas are also strongly positive for S100 protein. No reliable markers exist for oligodendrogliomas. Neurogenic tumors induced by MNU or ENU, as well as derived cell lines and clones from such tumors, have been successfully used as models for neurocarcinogenesis and therapeutic screening.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Characterization of N-nitrosourea-induced tumors of the nervous system; their prospective value for studies of neurocarcinogenesis and brain tumor therapy. 219 38

Mesenchymal chondrosarcoma is an uncommon small-cell neoplasm of bone and soft tissue, the chondrogenic nature of which has been generally accepted. However, the phenotypic attributes of the small-cell population in this neoplasm have not been well characterized, and its relationship to "precartilage mesenchyme" remains unclear. In an attempt to address this issue, we performed an immunohistochemical analysis of nine cases, using antibodies to vimentin, S100 protein, Leu-7 antigen, neuron-specific enolase, synaptophysin, desmin, muscle-specific actin, cytokeratin, and epithelial membrane antigen, and the avidin-biotin-peroxidase complex (ABC) method. The small cells of mesenchymal chondrosarcoma failed to express S100 protein, whereas all components of the tumors (small cells, lacunar chondroblasts, and chondroid matrix) stained for Leu-7 antigen in six cases. Neuron-specific enolase was identified in the small cells of four cases and in the lacunar cells of seven. None contained desmin, actin, cytokeratin, epithelial membrane antigen, or synaptophysin. The immunophenotype of mesenchymal chondrosarcoma resembled that of embryonic cartilage and thus did not contradict the premise that this tumor was the neoplastic counterpart of fetal chondroid tissues. However, immunohistologic studies are not overly helpful in the differential diagnosis between mesenchymal chondrosarcoma and other small round cell lesions.
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PMID:Mesenchymal chondrosarcoma. An immunohistochemical study. 220 75

A case of amelanotic malignant melanoma of the esophagus in a 76-year-old woman is reported. A whitish polypoid tumor, measuring 3 x 2 x 2.7 cm, surrounded by black pigmented mucosa, was detected in the middle intrathoracic esophagus. The tumor showed a lobulated surface lined by squamous cell layer, and had epithelioid and polyhedral cells forming alveolar clusters. Melanin pigments or stainability for the dihydroxyphenylalanine (DOPA) reaction were only observed in a few tumor cells. Junctional changes and mucosal melanosis, however, were found freely in the mucosa around the tumor. Many tumor cells showed a strongly positive immunohistochemical reaction for neuron specific enolase (NSE) and S100 protein. The patient died of widespread metastases six months after surgery. Further, a review of 106 reported cases of primary esophageal malignant melanoma, including 29 autopsies, was made; the melanomas were found to include 10 of amelanotic type, eight of which had been misdiagnosed at biopsy. Junctional changes could be found in the mucosa over or around the tumor, in four cases, and mucosal melanosis in one. Lymph node metastasis was the most frequently observed development at autopsy regardless of whether the tumor was amelanotic or melanotic. For correct diagnoses of melanomas of the amelanotic type, peripheral mucosal findings, such as junctional changes or melanosis, should be helpful; and, in order to obtain a good prognosis, a careful resection of the regional lymph nodes could prove valuable.
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PMID:Amelanotic malignant melanoma of the esophagus: case report and review of the literature. 225 5

Significance of the appearance of folliculo-stellate cells (FSC) was studied in 59 human adenohypophyses and 58 pituitary adenomas after being stained with anti-S100 protein and 6 anti-pituitary hormone antibodies. S100 protein positive cells, stellate in shape with expending cytoplasmic processes among endocrine cells (EC) appeared in all the human adenohypophyses and had a tendency to be clustered in small groups characterized by gathering of 3 to 5 cells in the alveoli. Age or sex difference seemed to have no influence on the distributive density of FSC. FSC in the pituitary adenomas may be derived from two origins. One was the residue of normal pituitary tissue left in adenomas, and the other one seemed to be the chief component of the tumor, known as folliculo-stellate cell adenoma.
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PMID:[Immunohistochemical study of folliculo-stellate cells in human adenohypophysis and in pituitary adenomas]. 227 9

Hyalinizing trabecular adenoma of the thyroid gland is an uncommon neoplasm that was recently described by Carney et al. (1987). It is important to recognize this tumor, considered benign, as it may mimic papillary carcinoma, medullary carcinoma or paraganglioma. We present two cases with histological and immunohistochemical criteria and discuss the diagnostic problems. Grossly, this small tumor is yellow tan and well circumscribed. The epithelial cells, polygonal or elongated and sharply outlined, have an eosinophilic or clear cytoplasm. The nuclei are oval or elongated, with often non-visible nucleoli. Grooved nuclei are quite frequent. Mitotic figures are very uncommon. The cells are arranged in clusters or trabeculae or pseudofollicles containing colloid material. Characteristically the cells, arranged shoulder to shoulder, can show a palisade pattern. The fibrovascular stroma appears hyaline, pseudoamyloid (Congo red staining is negative). The tumor cells show intense staining for thyroglobulin and no staining for thyrocalcitonin. Immunoreactivity for cytokeratin, vimentin, protein S100, NSE is positive but staining is negative for EMA and desmin. In one case, the tumor cells show little positivity for chromogranin A. The variable patterns of this tumor can lead to diagnostic problems. We can exclude the diagnosis of papillary carcinoma as this tumor lacks any true papillary architecture. We reject the diagnosis of medullary carcinoma because of its thyroglobulin and calcitonin immunoreactivity. Paraganglioma never shows immunoreactivity for thyroglobulin. Very often the surrounding thyroid tissue shows focal thyroiditis. The association of the tumor with Hashimoto's thyroiditis can be explained by an autoimmune process.
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PMID:[Hyalinizing trabecular adenoma of the thyroid gland. Histologic and immunohistochemical study. Report of 2 cases]. 228 55

A congenital primitive neuroectodermal tumor associated with epithelial and glial elements is described. This soft-tissue tumor present on the right temple of a newborn boy consisted mainly of small round cells of the primitive neuroepithelial type, occasionally forming rosettes. The other components were focal glandular structures producing mucin, and aggregates of epithelioid cells bearing clear cytoplasm, both being distributed throughout the entire tumor. Additional glandular and clear cell components were strongly positive for various epithelial markers, such as carcinoembryonic antigen, epithelial membrane antigen, and cytokeratin. Epithelioid cells were also positive for neuron-specific enolase and S100 protein. Glial differentiation was evidenced in some of the epithelioid cells by localization of cytoplasmic glial fibrillary acidic protein. These findings suggest that this tumor derives from a remnant of a neural crest, and the possibility of a special type of peripheral primitive neuroectodermal tumor is considered.
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PMID:Congenital primitive neuroectodermal tumor with epithelial and glial differentiation. An ultrastructural and immunohistochemical study. 229 64

To develop a reproducible in vivo model for the growth of human schwannomas we implanted tumor specimens from 14 different patients (13 acoustic neurinomas; 1 trigeminal schwannoma) into the subrenal capsule of 108 nude mice. In 11 experiments, the animals were implanted with only solid tumor from the surgical specimens. In two experiments, the tumor implants were made from solid tumors and cell clusters. In one experiment, the tumor implants were made from cell clusters alone. The size and neovascularization of these tumors were serially determined during a 1.5- to 3-month period. The percentages of tumors that survived or grew were 77.3% from solid tumors and 70% from cell clusters. Maximum tumor volume varied as did the time span to reach that volume. Tumor enlargement and stability correlated well with neovascularity; regressing tumor showed minimal or no neovascularity. Histological analysis of the implanted tumors showed spindle cells that are similar to the original tumor. Immunohistochemical staining for S100 demonstrated the Schwann cell nature of the implants. Analysis of genomic DNA from an acoustic neurinoma that had been implanted for 3 weeks was consistent with its human origin. There were no significant microscopic differences among groups receiving solid tumor implants or cell clusters. These studies suggest that implantation of human schwannomas into the subrenal capsule of the nude mouse is a reproducible method to study tumor growth that may be useful in testing potential therapeutic regimens or genetic modulation of schwannomas.
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PMID:Growth of human schwannomas in the subrenal capsule of the nude mouse. 233 81

The phenotypic characteristics of 7 subependymal giant cell astrocytomas (GSECG) (6 of these being associated with tuberous sclerosis) are studied using morphological and immunohistochemical methods with antiserums against vimentine, glial fibrillary acid protein (GFA), S100 protein, and neurofilaments. The glycoproteic secretion of the tumor cells was also analyzed after exposure to Concanavalin A (CON A) by a direct fluorescent method. Our results suggest that some GSECG originate from specialized ependyma (circum-ventricular organs). They have the same location (foramen of Monro), present some common ultrastructural features (cytoplasm with lumen containing cilia), are positive with certain immunohistochemical markers (staining with S100 protein in 4 cases, with vimentin in 3 cases) and show a strong glycoproteic secretion (positive with CON A). Therefore, some GSECG might be considered hamartomas of specialized ependyma, with a reduced evolutivity potential.
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PMID:[Histogenesis of subependymal glioma in Bourneville's tuberous sclerosis]. 234 68

Gingival granular cell tumor of the newborn, or congenital epulis, is a rare congenital lesion of uncertain histogenesis located exclusively on the alveolar ridge with marked predilection for female infants. Although histologically similar to the more ubiquitous granular cell tumor or myoblastoma, ultrastructural and immunohistochemical studies support separate histogenetic pathways for the two lesions. A newborn female infant with three gingival granular cell tumors is described herein along with immunohistochemical and ultrastructural observations. There was positive immunostaining for vimentin but staining for S100 protein was uniformly negative. Immunocytochemical assay for estrogen and progesterone receptors was also negative. The findings indicate a mesenchymal origin and the demonstration of intermediate filaments with fusiform electron densities suggests that some of the granular cells have morphologic attributes of myofibroblasts.
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PMID:Gingival granular cell tumors of the newborn. An ultrastructural and immunohistochemical study. 237 66

Formalin-fixed, paraffin-embedded tissue samples of canine amelanotic melanomas and normal canine tissues were studied immunohistochemically for the presence of S100 protein. Use of the avidin-biotin complex procedure demonstrated variable amounts of S100 protein in the tumor cell cytoplasm and nuclei in 26 of 31 tumors. S100 protein was not observed in some other common canine skin tumors stained by the avidin-biotin complex technique. These were a mast cell tumor, fibrosarcoma, mammary gland adenocarcinoma, histiocytoma, transmissible venereal tumor, and a thyroid gland adenocarcinoma. Among normal tissues the presence of S100 protein was demonstrated in chondrocytes in the trachea, myoepithelial cells in the breast, melanocytes in the skin, some sweat glands and ducts in the skin, stellate cells in the pituitary, and interdigitating reticulum cells in the lymph node and in Peyer's patches. These results indicate that the avidin-biotin complex procedure for demonstrating S100 protein is a useful diagnostic tool in the diagnosis of canine amelanotic melanoma.
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PMID:Immunohistochemical staining for S100 protein in the diagnosis of canine amelanotic melanoma. 241 99


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