SEARCH · PubMed Health
Results for “THYMUS NEOPLASMS”
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Early onset of neoplasia in the prostate and skin of mice with tissue-specific deletion of Pten.
PTEN is a tumor suppressor gene mutated in various advanced human neoplasias, including glioblastomas and prostate, breast, endometrial, and kidney cancers. This tumor suppressor is a lipid phosphatase that negatively regulates cell survival and proliferation mediated by phosphatidylinositol 3-kinase/protein kinase B signaling. Using the Cre-loxP system, we selectively inactivated Pten in murine tissues in which the MMTV-LTR promoter is active, resulting in hyperproliferation and neoplastic changes in Pten-null skin and prostate. These phenotypes had early onset and were completely penetrant. Abnormalities in Pten mutant skin consisted of mild epidermal hyperplasia, whereas prostates from these mice exhibited high-grade prostatic intraepithelial neoplasia (HGPIN) that frequently progressed to focally invasive cancer. These data demonstrate that Pten is an important physiological regulator of growth in the skin and prostate. Further, the early onset of HGPIN in Pten mutant males is unique to this animal model and implicates PTEN mutations in the initiation of prostate cancer. Consistent with high PTEN mutation rates in human prostate tumors, these data indicate that PTEN is a critical tumor suppressor in this organ.
Guidelines for the management of gastroenteropancreatic neuroendocrine tumours (including bronchopulmonary and thymic neoplasms). Part I-general overview.
The incidence of neuroendocrine tumours of the gastroenteropancreatic system seems to have increased during the past decade. New diagnostic and therapeutic procedures have aroused the interest of physicians, though most see very few cases of such diseases. A group of members of the Nordic Neuroendocrine Tumour Group decided to compile some guidelines to facilitate the diagnosis and treatment of patients with these tumours. Part I of these guidelines discusses the principles of histopathology, biochemical and radiological diagnosis as well as therapeutic options.
Guidelines for the management of gastroenteropancreatic neuroendocrine tumours (including bronchopulmonary and thymic neoplasms). Part II-specific NE tumour types.
Part II of the guidelines contains a description of epidemiology, histopathology, clinical presentation, diagnostic procedure, treatment, and survival for each type of neuroendocrine tumour. We are not only including gastroenteropancreatic tumours but also bronchopulmonary and thymic neuroendocrine tumours. These guidelines essentially cover basic knowledge in the diagnosis and management of the different forms of neuroendocrine tumour. We have, however, tried to give more updated information about the epidemiology and histopathology, which is essential for the clinical management of these tumours.
Association of a wide invasive malignant thymoma with myastenia gravis and primary hyperparathyroidism due to parathyroid adenoma: case report and review of the literature.
There are few cases described in the world literature reporting an association of thymoma (with myasthenia gravis or not) with hyperparathyroidism. In these cases the hyperparathyroidism was due to the presence of an adenoma or hyperplasic parathyroid tissue either in the cervical region or in an ectopic intrathymic location.(12345) In other cases the syndrome of hypercalcemia was due to the secretion of parathyroid-related protein (PTHRP) (6) or parathyroid hormone (PTH) (7) by the thymoma itself. We report the first case, at the best of our knowledge, of a wide invasive malignant thymoma (type B3), associated with myasthenia gravis and hyperparathyroidism caused by parathyroid adenoma.
Thymic carcinoid in the pancreas: metastatic disease or new primary tumours.
Explore the source record for details and available documents.
Mediastinal large B-cell lymphoma vs classic Hodgkin lymphoma.
Explore the source record for details and available documents.
Cell culture from a rat brain tumor induced by intracerebral inoculation with murine sarcoma virus.
Explore the source record for details and available documents.
Multimodal treatment of metastatic thymic carcinoma including high-dose chemotherapy with autologous stem cell transplantation: report of a case with more than 4-year disease-free survival.
Thymic carcinoma is a rare epithelial malignancy differentiated from thymoma by the presence of cytologically malignant cells. There are few reports of the treatment of locally advanced or metastatic thymic carcinoma. We describe a patient who sought treatment for thymic carcinoma metastatic to pleura, pericardium, retroperitoneum, and neck nodes. He was treated with neoadjuvant etoposide, ifosfamide, and cisplatin, and underwent resection. We then administered high-dose chemotherapy with autologous stem cell support, followed by radiation therapy. The patient remains in complete remission more than 4 years after diagnosis. To our knowledge, this is the first report of metastatic thymic carcinoma treated with neoadjuvant therapy and postoperative high-dose chemotherapy. Metastatic thymic carcinoma may be curable by aggressive combined therapies.
Ectopia of primary thymic tumors.
Explore the source record for details and available documents.
Metabolic (PET) and receptor (SPET) imaging of well- and less well-differentiated tumours: comparison with the expression of the Ki-67 antigen.
[111In-DTPA-D-Phe1]-pentetreotide has been shown to localize well-differentiated and slowly growing neuroendocrine tumours, whereas increased FDG uptake is associated with malignancy. This prospective study explores the role of metabolic (PET) and receptor (SPET) imaging in well- and less well-differentiated tumours--gastroenteropancreatic (GEP) tumours, medullary thyroid carcinomas (MTC) and thymic carcinomas--in comparison with the expression of the Ki-67 antigen. Ten patients with GEP tumours, five with MTC and five with thymic carcinomas were studied. Prior to PET, somatostatin receptor scintigraphy (SRS) was performed in all patients. Sixty minutes after the intravenous administration of 18F-FDG (370 MBq), whole-body PET was performed. In addition, the resected tissues were prepared for immunocytochemistry examination (cell cycle-associated Ki-67 antigen). Preoperative SRS detected multiple primary tumours and metastatic lesions in four patients with well-differentiated carcinoids (low Ki-67 expression). Whole-body PET demonstrated normal distribution of FDG in all of these patients. In patients with recurrent MTC and rapidly increasing CEA levels, SRS showed no in vivo somatostatin receptor expression, whereas whole-body PET localized 24 locoregional lymph node metastases with increased FDG uptake. Immunocytochemistry of the resected lymph nodes demonstrated high Ki-67 expression associated with a high proliferative activity. Similar results in receptor scintigraphic and metabolic behaviour were obtained from patients with metastasizing thymic carcinomas (high Ki-67 expression). In conclusion, SRS has been shown to localize well-differentiated GEP tumours. In contrast, FDG PET is only valuable for predicting malignancy in less well-differentiated GEP tumours and malignant MTC associated with rapidly increasing CEA levels. Therefore, an additional 18F-FDG PET procedure should only be performed if SRS is negative. Furthermore, our preliminary results suggest that increased FDG metabolism reflects the invasiveness of thymic carcinomas.
CT/MRI of neuroendocrine tumours.
Neuroendocrine tumours (NETs) are often thought to be rare and rather recherché cancers which are of little concern to the general physician, surgeon or radiologist because of their rarity and esoteric nature. In fact, while relatively uncommon, the total group of gastro-entero-pancreatic (GEP) tumours incorporates the spectrum of all types of carcinoids, including bronchial carcinoids, and the whole gamut of islet-cell tumours. Some of these may present as functioning tumours, with a plethora of hormonal secretions and concomitant clinical syndromes, and GEPs in general have an incidence around 30 per million population per year. This means that in the whole European Union, for example, there will be in the region of 12,000 new patients every year presenting with one or another manifestation of these tumours. Furthermore, the comparatively long survival of many of these patients, compared to more common adenocarcinomas or epithelial tumours, implies that the point prevalence is also not inconsiderable. However, it is undoubtedly true that these tumours can be difficult to identify, especially in their early stages, and it is then that radiological investigation becomes of paramount importance. Having taken into account all these considerations, most investigators would initiate investigation of a suspected or biochemically proven islet-cell tumour with cross-sectional imaging-either CT or MRI. This will clearly identify the larger lesions, allow assessment of the entire abdomen, and provide valuable information on the presence of hepatic metastates.
Intracytoplasmic and extracytoplasmic lumina with a peripheral halo and spikes (spicular bodies) found in epithelial tumors.
Intracytoplasmic lumina, each with a peripheral halo and spikes, a hitherto undescribed histological structure, were found in several human carcinomas. Similar structures found at the free surfaces of carcinoma cells, or those composed of several individual carcinoma cells, were designated extracytoplasmic lumina with a peripheral halo and spikes. Haloes were seen along the cytoplasm around the lumina, and the spikes penetrated into the cytoplasmic haloes. Transmission electron microscopy revealed that these spicular bodies were lumina equipped with microvilli containing an actin core. Spicular bodies were found in the following neoplasms; 22% of hepatocellular carcinomas (11/50), 35% of colonic adenocarcinomas (7/20), 31% of gastric adenocarcinomas (16/51). In contrast, no or only very occasional spicular bodies were found in thyroid (0/20) and mammary (1/22) adenocarcinomas. Although the diagnostic value of this structure is unknown at the present time, its identification in a carcinoma may be a histologic indicator of its endodermal nature.
Evolution of immune surveillance and tumor immunity: studies in Xenopus.
We have developed a novel experimental model of cancer immunity in the frog, Xenopus, which may provide a useful alternative to murine tumor models and a way to assess whether the control of tumor development is a fundamental function of the immune system of vertebrates. In Xenopus, tumor immunity can be studied in two developmentally distinct immune systems. The larval immune system reflects characteristics of an ancestral system that appears to function without classical MHC class I antigen presentation and an efficient effector mechanism. The adult system appears more highly evolved in that it is remarkably similar to that of mammals and is able to generate a potent antitumor response. This amphibian model also provides a unique system with which to investigate a postulated role of heat shock proteins as components of an ancestral system of antigen presentation and/or immune surveillance that predates the antigen presentation pathway that exclusively involves MHC molecules.
Parathyroid-hormone-related-protein-producing thymic carcinoma presenting as a giant extrathoracic mass.
A 53-year-old female with a 9-month history of chest pain presented with a giant anterior chest wall mass. Radiologic examination showed an anterior mediastinal tumor invading the chest wall. Serum calcium and parathyroid hormone-related protein (PTHrP) levels were extremely elevated. Biopsy specimens disclosed a squamous cell carcinoma with Hassall's corpuscle-like keratotic pearls, and an immunohistological study showed a positive staining with PTHrP. The tumor and serum PTHrP concentration markedly decreased following cisplatin-based chemotherapy and radiation. This is the first case of PTHrP producing a thymic carcinoma with the unusual presentation of a large extrathoracic mass.
Some pathological aspects of the spontaneous lymphoid tumour in Xenopus laevis.
Explore the source record for details and available documents.
On pericardial lymphangiomas.
Explore the source record for details and available documents.
Karnofsky Memorial Lecture. Breaking the cure barrier.
Breaking the cure barrier is a biologic and a conceptual problem that has already been accomplished for several tumors. It is helpful to consider neoplasms in mathematical terms as many-celled tumors (polycytomas: kilocytomas, megacytomas, gigacytomas, and teracytomas). A new chemotherapeutic taxonomy recognizes curable, subcurable, and precurable cancers each with definable characteristics. A simplified technique of recognizing early cures is described by calculating the probability that an interruption in an exponential failure slope occurred by chance. Examples of cures of acute myelocytic leukemia, of superior chemotherapy for Hodgkin's disease in young adults, and of superior adjuvant chemotherapy for breast cancer are given. The interaction of surgery with chemotherapy is illustrated in pure form in acute myelocytic leukemia and in ovarian cancer. Curative chemotherapy is closer at hand than is generally believed. Nomograms for cure prediction are presented as inducements to contemplate curative approaches to cancer therapy.