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At least 127 records · Page 7Linked to original sources
PubMed2001

Multiple allelic deletions and intratumoral genetic heterogeneity in men1 pancreatic tumors.

Multiple endocrine neoplasia type 1 (MEN1) is an inherited syndrome with multiple tumors of the endocrine pancreas, the parathyroid, the pituitary, and other tissues. The MEN1 gene at 11q13 is homozygously mutated in the majority of MEN1 tumors. Here we present a genome-wide loss of heterozygosity (LOH) screening of 23 pancreatic lesions, one duodenal tumor, and one thymic carcinoid from 13 MEN1 patients. Multiple allelic deletions were found. Fractional allelic loss varied from 6-75%, mean 31%. All pancreatic tumors displayed LOH on chromosome 11, whereas the frequency of losses for chromosomes 3, 6, 8, 10, 18, and 21 was over 30%. Different lesions from individual patients had discrepant patterns of LOH. Intratumoral heterogeneity was revealed, with chromosome 6 and 11 deletions in most tumor cells, whereas other chromosomal loci were deleted in portions of the analyzed tumor. Chromosome 6 deletions were mainly found in lesions from patients with malignant features. Fractional allelic loss did not correlate to malignancy or to tumor size. Our findings indicate that MEN1 pancreatic tumors fail to maintain DNA integrity and demonstrate signs of chromosomal instability.

Adult↗
PubMed2004

Thymic carcinoma presenting as cranial metastasis with intradural and extracranial extension: case report.

OBJECTIVE AND IMPORTANCE: Thymic carcinoma is an uncommon malignant tumor that is different from thymoma. Cranial and brain metastases from this tumor are extremely rare. We report a thymic carcinoma with cranial metastasis and discuss the behavior of this tumor. CLINICAL PRESENTATION: A 50-year-old man presented with headache and a palpable scalp tumor. Computed tomographic scans and magnetic resonance images revealed an osteolytic tumor with intradural and extracranial extension in the right occipital bone. INTERVENTION: After gross total resection and histological diagnosis, further investigation revealed a primary thymic tumor in the anterior upper mediastinum and liver metastases. The patient received multiple-cycle chemotherapy (cisplatin and gemcitabine) for primary and metastatic lesions. CONCLUSION: Thymic carcinoma has a poor prognosis because of a high degree of malignancy, early metastasis, and delayed diagnosis. Thus, treatment of a patient with this tumor calls for prompt diagnosis, surgical treatment, and optimal adjuvant therapy.

Carcinoma↗
PubMed1991

ras activation in human tumors and in animal model systems.

Environmental agents such as radiation and chemicals are known to cause genetic damage. Alterations in a limited set of cellular genes called proto-oncogenes lead to unregulated proliferation and differentiation. We have studied the role of the ras gene family in carcinogenesis using two different animal models. In one case, thymic lymphomas were induced in mice by either gamma or neutron radiation, and in the other, keratoacanthomas were induced in rabbit skin with dimethylbezanthracene. Human keratoacanthomas similar to the ones induced in rabbits were also analyzed. We found that different types of radiation such as gamma rays and neutrons, induced different point mutations in ras genes. A novel K-ras mutation in codon 146 has been found in thymic lymphomas induced by neutrons. Keratoacanthomas induced in rabbit skin by dimethylbenzanthracene show a high frequency of H-ras-activated genes carrying a mutation in codon 61. The same is observed in human keratoacanthomas, although mutations are in both the 12th and the 61st codons of the H-ras gene. H-ras activation is less frequent in human squamous cell carcinomas than in keratoacanthomas, suggesting that ras genes could play a role in vivo in differentiation as well as in proliferation.

3T3 Cells↗
PubMed1999

Thymic carcinoma of the thymic hormone secretory type in a cow.

An 8-year-old Holstein cow had tumor nodules and enlarged lymph nodes in the mediastinum, and metastatic tumor masses in the pelvic cavity. The neoplastic cells were characterized by squamous features and intracytoplasmic vacuoles carrying microvilli, some of which contained periodic acid Schiff-positive globular cores, but tubular structures or goblet cells were absent. Many neoplastic cells stained positively for keratin, and occasional cells were positive for thymosin. The presence of secretory granules in the cytoplasm was confirmed by electron microscopy. This neoplasm was considered to be of thymic hormone-secreting epithelial cell origin.

Animals↗
PubMed2001

Giant cell hepatitis in two young cats.

A very rare case of the liver lesion characterized by formation of multinucleated giant hepatocytes with inflammatory cell infiltration were observed in two young (1.5 years and 2 years old) cats bearing thymic malignant lymphoma. Histopathological features of this liver lesion were very similar to giant cell hepatitis (GCH) in human neonates and infants. Therefore, the lesion was diagnosed as feline GCH.

Animals↗
PubMed1996

Thymic carcinoma which developed in a thymic cyst.

Thymic carcinoma was found in a thymic cyst in a 60-year-old woman who was admitted to our hospital due to cough and pain in her right chest. Chest X-ray showed a huge shadow in the right mediastinum. Chest CT scan showed a cystic tumor with a solid mass. An operation revealed a solid tumor in the thymic cyst. Pathologic diagnosis was squamous cell carcinoma, that contained some glandular tissues. The patient has been in a good condition for two years after the operation. Although the concurrent occurrence of thymic carcinoma and thymic cyst is very rare, it should be added to the differential diagnosis when anterior mediastinal cystic tumor is associated with a solid mass lesion.

Aged↗
PubMed1993

Carcinogenicity of benzotrichloride administered to mice by gastric intubation.

Epidemiological studies suggest that benzotrichloride (BTC) is a human carcinogen. In the present study, BTC was tested to evaluate its ability to induce lung tumors as a result of systemic exposure. Administration of BTC by gastric intubation, 2.0-0.0315 microliters/mouse (4 doses), twice a week for 25 weeks, in female ICR mice, produced forestomach tumors (squamous cell carcinoma and papilloma), lung tumors (adenocarcinoma and adenoma) and tumors of the hematopoietic system (thymic lymphosarcoma and lymphatic leukemia) with dose-related response by 18 months. The present and previous studies indicate that the target organs of BTC carcinogenesis in mice are the local tissue which is primarily exposed, and the lung and hematopoietic tissue when BTC is administered systematically.

Administration, Oral↗
PubMed1975

Teratomas in childhood.

Of 107 teratomas in children, 86 were benign and 21 malignant. Sacrococcygeal and pelvic teratomas predominated (51 cases) and these fell into 3 groups: post sacral, dumb-bell and presacral. The 34 purely posterior tumours were always congenital and benign, whilst the incidence of malignancy in dumb-bell and presacral teratomas increased as the tumour became more internal. Malignant teratomas were carcinomas, usually containing glandular, papillary and clear-cell areas, and metastases were similar. Immature tissues in benign teratomas were usually neural or connective tissue. They did not give rise to neuroblastomas or sarcomas, and did not indicate a worse prognosis. Only 2 originally benign teratomas later developed malignancy.

Adolescent↗
PubMedDate not supplied

Malignant mesenchymoma associated with an unusual vasoinvasive metastasis in a dog.

A case of a malignant mesenchymoma with an unusual, vasoinvasive, metastatic behavior in a three-year-old, intact female basset hound is presented. Malignant mesenchymomas are rare neoplasms in humans and in dogs. No previous reports of a malignant mesenchymoma with vasoinvasive metastasis in the dog were found in the literature. The constituent neoplasms are discussed in relation to reports in the human and veterinary literature, and a potential etiology for this unique presentation is hypothesized.

Animals↗