PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Multiple Endocrine Neoplasia Type 2b”

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.

At least 91 records · Page 5Linked to original sources
PubMedDate not supplied

Malignant pheochromocytoma in multiple endocrine neoplasia type 2B syndrome. Case report and review of the literature.

A malignant behavior (i.e., distant metastatic spread) has been recorded in 3-4% pheochromocytomas occurring in the context of multiple endocrine neoplasia type 2A syndrome, but has never been documented in patients with the type 2B form. In this report we describe a case of malignant pheochromocytoma arising in the latter syndrome setting. The patient, a white young male, had the full-blown syndrome, including multicentric, bilateral medullary thyroid carcinoma metastatic to regional lymph nodes, mucosal neuromas, digestive ganglioneuromatosis, marfanoid habitus, and bumpy lips. Three and a half years after surgical resection of an apparently benign adrenal pheochromocytoma he developed widespread osseous metastases. The presence of hypertensive crises and high urinary catecholamine excretion rates, coupled to moderate hypercalcitoninemia, normal circulating carcinoembryonic antigen levels, negative whole-body 99mTc-(V) dimercaptosuccinic acid scan, and absence of neck or mediastinal disease by magnetic resonance imaging, proved that the metastases were from his previous adrenal and not thyroid tumor. Furthermore, since the bone metastases strongly accumulated 131I-metaiodobenzylguanidine, several courses of the radiocompound were given, which resulted in an objective, though partial, tumor regression.

Adrenal Gland Neoplasms↗
PubMed2006

Multiple endocrine neoplasia type 2B diagnosed on suction rectal biopsy in infancy: a report of 2 cases.

Suction rectal biopsies in a newborn and a 10-month-old infant presenting with intestinal obstruction showed marked increase in neurons and nerve bundles in the submucosa. Although there were no syndromic features or a positive family history, mutation analysis of the RET proto-oncogene showed a de novo germline Met918Thr mutation in both patients, confirming the diagnosis of multiple endocrine neoplasia type 2B (MEN 2B). Thyroidectomy was performed at 9 and 14 months, showing medullary carcinoma and focal prominent C-cell hyperplasia, respectively. These 2 cases are presented to emphasize that when the submucosal plexus is obviously and prominently increased in suction rectal biopsies, diffuse intestinal ganglioneuromatosis should be considered. As this can be associated with genetic conditions, especially MEN 2B, it is crucial that further investigations be performed to ensure proper patient management, such as early thyroidectomy.

Biopsy, Needle↗
PubMed2005

Case report: multiple endocrine neoplasia type 2B misdiagnosed as familial dysautonomia.

BACKGROUND: Familial dysautonomia (FD) is a rare autosomal recessive disorder of the peripheral nervous system, affecting exclusively Jewish children of Ashkenazi extraction. The typical clinical features consist of somatic abnormalities: failure to thrive, characteristic facies, excessive sweating, labile blood pressure, recurrent aspiration pneumonias, lack of tears, and diminished and later absent deep tendon reflexes with generalized reduction of pain sensation. Oro-dental features include a lack of tongue fungiform papillae, impairment of taste, oro-dental self-mutilation, dental crowding, excessive plaque and calculus accumulation, salivary over production and low caries experience. CASE REPORT: A child with multiple endocrine neoplasia type 2B (MEN 2B) received, at the age of 11 months, an incorrect diagnosis of familial dysautonomia (FD). At the age of 6 years, a paediatric dentist experienced with FD noticed a normal number and shape of tongue fungiform papillae, while expecting to find a smooth tongue lacking those structures. The presence of numerous submucosal neuromata initiated a meticulous neurological and endocrine work-up, which established the diagnosis of MEN 2B. This led to an early detection and appropriate treatment of asymptomatic medullary thyroid carcinoma (MTC).

Adolescent↗
PubMed1997

The multiple endocrine neoplasia type 2B point mutation switches the specificity of the Ret tyrosine kinase towards cellular substrates that are susceptible to interact with Crk and Nck.

The RET proto-oncogene encodes a Tyrosine Kinase Receptor (RTK) which plays an important function in the proliferation and/or differentiation of neuroectodermic cells. Germline mutation of a methionine to a threonine within the RET TK domain predisposes to the Multiple Endocrine Neoplasia type 2B (MEN 2B). It has been demonstrated that, unlike c-Ret, the MEN 2B mutated Ret displays constitutive TK activity, tyrosine autophosphorylation and transforms fibroblasts. However, this oncoprotein is more than a fully activated wild-type (WT) Ret TK since it also displays modified substrate specificity. Change in substrate specificity leads to the tyrosine autophosphorylation of MEN 2B Ret on new sites as well as the phosphorylation of several novel downstream targets. But, none of these substrates have been identified and the ability of MEN 2B Ret phosphoprotein to interact with Src Homology 2 (SH2) domain containing molecules has been poorly investigated. In this report, using a constitutively activated Ret TK form, Ret-ptc 2, we demonstrate that the MEN 2B as the activated WT Ret TK binds to several SH2 signalling proteins such as Shc, Grb-2, Phospholipase Cgamma, Crk and Nck. However, in contrast to the activated WT form, expression of the MEN 2B mutated Ret-ptc 2 results in the tyrosine phosphorylation of a panel of proteins which interestingly interact with Crk and Nck. We identified Paxillin, a cytoskeletal protein as one of the Crk associated proteins that is dramatically phosphorylated in MEN 2B but not in WT Ret expressing cells. These data suggest that MEN 2B mutated Ret triggers distinct signalling pathways that might be related to its transforming power.

Adaptor Proteins, Signal Transducing↗
PubMed1999

Biological and biochemical properties of Ret with kinase domain mutations identified in multiple endocrine neoplasia type 2B and familial medullary thyroid carcinoma.

Several mutations were identified in the kinase domain of the RET proto-oncogene in patients with multiple endocrine neoplasia (MEN) 2B, familial medullary thyroid carcinoma (FMTC) or sporadic medullary thyroid carcinoma. We introduced seven mutations (glutamic acid 768-->aspartic acid (E768D), valine 804-->leucine (V804L), alanine 883-->phenylalanine (A883F), serine 891-->alanine (S891A), methionine 918-->threonine (M918T), alanine 919-->proline (A919P) and E768D/A919P) into the short and long isoforms of RET cDNA and transfected the mutant cDNAs into NIH3T3 cells. The transforming activity of the long isoform of Ret with each mutation was much higher that that of its short isoform. Based on the levels of the transforming activity, these mutant RET genes were classified into two groups; a group with high transforming activity (A883F, M918T and E768D/A919P) and a group with low transforming activity (E768D, V804L, S891A and A919P) (designated high group and low group). Interestingly, the level of transforming activity correlated with clinical phenotypes; high group Ret with the A883F or M918T mutation and low group Ret with the E768D, V804L or S891A mutation were associated with the development of MEN 2B and FMTC, respectively. In addition, we found that substitution of phenylalanine for tyrosine 905 present in the kinase domain abolished both transforming and autophosphorylation activities of low group Ret whereas it did not affect the activities of high group Ret.

Amino Acid Substitution↗
PubMed2004

Expression profiles provide insights into early malignant potential and skeletal abnormalities in multiple endocrine neoplasia type 2B syndrome tumors.

Identifying the molecular basis for genotype-phenotype correlations in human diseases has direct implications for understanding the disease process and hence for the identification of potential therapeutic targets. To this end, we performed microarray expression analysis on benign (pheochromocytomas) and malignant (medullary thyroid carcinomas, MTCs) tumors from patients with multiple endocrine neoplasia (MEN) type 2A or 2B, related syndromes that result from distinctive mutations in the RET receptor tyrosine kinase. Comparisons of MEN 2B and MEN 2A MTCs revealed that genes involved in the process of epithelial to mesenchymal transition, many associated with the tumor growth factor beta pathway, were up-regulated in MEN 2B MTCs. This MEN 2B MTC profile may explain the early onset of malignancy in MEN 2B compared with MEN 2A patients. Furthermore, chondromodulin-1, a known regulator of cartilage and bone growth, was expressed at high levels specifically in MEN 2B MTCs. Chondromodulin-1 mRNA and protein expression was localized to the malignant C cells, and its high expression was directly associated with the presence of skeletal abnormalities in MEN 2B patients. These findings provide molecular evidence that associate the previously unexplained skeletal abnormalities and early malignancy in MEN 2B compared with MEN 2A syndrome.

Gene Expression Profiling↗
PubMed1987

[A case report of multiple endocrine neoplasia type 2b].

A 10-year-old girl was admitted displaying a medullary thyroid carcinoma, accompanying neurinomas of the tongue, marfanoid habitus, megacolon, and scoliosis. Although her adrenal glands were found to be unremarkable on both CT and ultrasonogram examination an MIBG scintiscan showed a 131-1 uptake, suggesting the presence of medullary hyperplasia. Remarkable nodal involvement with invasive features witnessed in the upper mediastinum during tertiary surgery four years later, following a total thyroidectomy. The TCT and CEA profiling was not sufficient enough to predict a recurrence. At the present state there is difficulty in providing an early diagnosis; through node dissection, however, is considered to be necessary at time of primary thyroid operation in cases with MEN type 2b.

Carcinoma↗
PubMed1992

Multiple endocrine neoplasia syndrome--type 2b. Case report and review.

The multiple endocrine neoplasia syndromes are an association of tumours of 2 or more endocrine glands. Multiple endocrine neoplasia type 2b (MEN 2b) patients develop medullary thyroid carcinoma and pheochromocytomas as well as unique physical characteristics. Most commonly, MEN2b is inherited with an autosomal dominant pattern although sporadic cases are not uncommon. If untreated the disease may be lethal. The facial, oral and ocular characteristics are reliable markers of the disease. These patients give a history most commonly of slipped capital femoral epiphysis, hypertension and life-long diarrhoea and/or constipation. MEN2b is most commonly characterised by nodules on the anterior aspect of the tongue, thickened lips with nodules, thickened upper eyelids, broadened nasal bridge, thickened corneal nerves and dilated, symmetrical, pedunculated nodules on the cheek mucosa. The patient described has most of these characteristics. Radiographic features of the jaws which have not been previously described are reported. These include a markedly enlarged and bifurcated inferior alveolar canal and shortened roots of the lower incisor teeth. Due to the lethality of the disease, patients who present with the above physical characteristics must be further investigated to exclude MEN2b.

Adrenal Gland Neoplasms↗
PubMed1996

RET protooncogene mutational analysis in multiple endocrine neoplasia syndrome type 2B: case report and review of the literature.

Multiple endocrine neoplasia, type 2B (MEN 2B), is a phenotypic variant of a group of autosomal-dominant neurocristopathies. MEN 2B is associated with medullary thyroid carcinoma and pheochromocytoma with oral, ocular, and alimentary submucosal ganglioneuromas and Marfanoid body features. Approximately 50% of cases are thought to be spontaneous mutations. The RET protooncogene (RET) is a 21-exon gene encoding a tyrosine kinase receptor. A codon 918 germ line mutation, which converts a highly conserved methionine to a threonine in the intracellular tyrosine kinase portion of this receptor of RET, has been identified in 95% of patients with MEN 2B. This mutation is easily detected by a direct deoxyribonucleic acid sequencing or restriction enzyme (Fok 1) analysis of amplified polymerase chain reaction products. The RET gene is normally expressed in the oral and gastrointestinal submucosal neural ganglia, and the codon 918 mutation is thought to cause neuromas by virtue of its transforming activity in these ganglia. Identifying clinical features of MEN 2B in an 11-year-old boy by an oral pathologist led to confirmation by mutational analysis. Before genetic testing was available, the patient, and at a later date his mother, underwent thyroidectomies based solely on biochemical testing. Results indicated the patient had the codon 918 mutation, whereas his phenotypically normal mother, father, and older brother had normal RET analyses. Studies in families have demonstrated that the mutant allele is derived from the father with possible acquisition during spermatogenesis. We believe the mother of our affected patient to be normal; the absence of phenotypic features of MEN 2B and a normal genotype suggest her calcitonin abnormalities and minimal evidence for C-cell hyperplasia were inconsequential. Molecular analysis for RET abnormalities will likely supplant biochemical methods of diagnosis in patients with MEN 2B.

Carcinoma, Medullary↗
PubMed1988

Scintigraphic portrayal of the syndrome of multiple endocrine neoplasia type-2B.

The scintigraphic appearance of the neoplasms in multiple endocrine neoplasia type 2B (MEN-2B) and the interpretations of the image patterns are described. An 18-year-old male patient with the MEN-2B syndrome underwent TI-201 imaging that showed concentrations of TI-201 in the primary medullary thyroid carcinoma (MTC) tumor and in cervical lymph node metastases. After total thyroidectomy and lymph node dissection, the TI-201 image was normal. Catecholamine levels in the blood and urine were only borderline elevated. Yet, greater than normal concentrations of I-131 metaiodobenzylguanidine (I-131 MIBG) were present in both adrenal glands. Computed tomography of the abdomen showed normal adrenal glands. These results were consistent with the diagnosis of adrenal medullary hyperplasia, a precursor of pheochromocytoma. No operation was indicated to remove the adrenal glands. Imaging with TI-201 appears to be useful in identifying sites of MTC in patients with the MEN-2B syndrome. I-131 MIBG imaging, in conjunction with computed tomography of the adrenal glands and appropriate catecholamine measurements, should be performed in patients with the MEN-2B syndrome to determine the status of the adrenal medullae, which then may be classified as normal, hyperplastic, or tumorous with pheochromocytoma.

3-Iodobenzylguanidine↗
PubMedDate not supplied

[Clinical and genetic profile of patients with medullary thyroid cancer treated in the Cancer Centre--Institute of Oncology in Warsaw].

INTRODUCTION: The aim of this study was to analyse the distribution and frequency of mutations and their correlations with clinical phenotypes of patients with MTC, to reveal the differences between sporadic and familial type of MTC, and to describe the phenotypes of patients. MATERIALS AND METHODS: 212 patients with medullary thyroid cancer (MTC) were treated in Cancer Centre in Warsaw between 1997 and 2005. In most patients, DNA isolated from peripheral blood leukocytes was tested for RET gene mutations by sequencing and accordingly MTC form was assessed. Genetic testing was performed in the relatives of patients with familial MTC in order to distinguish asymptomatic mutation carriers from noncarriers. RESULTS: RET gene mutations were identified in 46 patients (22%). The others were found noncarriers and sporadic MTC was diagnosed. MEN 2A/FMTC syndrome (multiple endocrine neoplasia type 2A/ familial type of MTC) was diagnosed in 44 patients, MEN 2B syndrome (multiple endocrine neoplasia type 2B) in 2 patients. In patients with sporadic and familial MTC, age at diagnosis and multifocal occurrence was analysed, and the results were found to be in accordance with those of other research centres. However, the distribution and frequency of mutations, as well as some clinical data, such as the frequency of pheochromocytoma occurrence as the first manifestation of MEN syndrome, differed from the published data, and further studies are necessary to reveal the reasons of these differences. CONCLUSIONS: DNA testing for RET gene mutations is reliable as a diagnostic tool and therefore it should be performed for screening of all patients with MTC or other diseases of MEN syndrome.

Adolescent↗