Hereditary medullary thyroid carcinoma syndromes: experience from western India.

The data from the Indian subcontinent on Medullary thyroid carcinoma (MTC) and associated endocrinopathies in hereditary MTC (HMTC) syndromes are limited. Hence, we analyzed clinical and biochemical characteristics, management, and outcomes of HMTC and other associated endocrinopathies [Pheochromocytoma (PCC) and Primary hyperparathyroidism (PHPT)] and compared with apparently sporadic MTC. The records of 97 (51 sporadic and 46 hereditary) consecutive MTC patients were retrospectively analyzed. RET mutation was available in 38 HMTC patients. HMTC group was subclassified into Multiple endocrine neoplasia (MEN) 2A index (n = 25), MEN2B index (n = 8), and MEN2A detected by familial screening (n = 12). Patients with HMTC and MEN2B index were younger at presentation than sporadic MTC. MEN2A patients detected by familial screening, but not MEN2A index and MEN2B index patients, had significantly lower serum calcitonin, smaller thyroid nodule size, more frequent early stage presentation (AJCC Stage ≤ II), and higher cure rate than sporadic MTC, which emphasizes the need for early diagnosis. RET (REarranged during Transfection) 634 mutations were the most common cause of HMTC and more frequently associated with PCC (overall 54% and 100% in those aged ≥ 35 years). Patients in ATA-Highest (HST) group had a universal presentation in stage IV with no cure. In contrast, the cure rate and postoperative disease progression (calcitonin doubling time) were similar between ATA-High (H) and ATA- Moderate (MOD) groups, suggesting the need for similar follow-up strategies for the latter two groups. Increased awareness of endocrine (PCC/PHPT) and non endocrine components may facilitate early diagnosis and management.

Evolution of Our Understanding of the Hyperparathyroid Syndromes: A Historical Perspective.

We review advancing and overlapping stages for our understanding of the expressions of six hyperparathyroid (HPT) syndromes: multiple endocrine neoplasia type 1 (MEN1) or type 4, multiple endocrine neoplasia type 2A (MEN2A), hyperparathyroidism-jaw tumor syndrome, familial hypocalciuric hypercalcemia, neonatal severe primary hyperparathyroidism, and familial isolated hyperparathyroidism. During stage 1 (1903 to 1967), the introduction of robust measurement of serum calcium was a milestone that uncovered hypercalcemia as the first sign of dysfunction in many HPT subjects, and inheritability was reported in each syndrome. The earliest reports of HPT syndromes were biased toward severe or striking manifestations. During stage 2 (1959 to 1985), the early formulations of a syndrome were improved. Radioimmunoassays (parathyroid hormone [PTH], gastrin, insulin, prolactin, calcitonin) were breakthroughs. They could identify a syndrome carrier, indicate an emerging tumor, characterize a tumor, or monitor a tumor. During stage 3 (1981 to 2006), the assembly of many cases enabled recognition of further details. For example, hormone non-secreting skin lesions were discovered in MEN1 and MEN2A. During stage 4 (1985 to the present), new genomic tools were a revolution for gene identification. Four principal genes ("principal" implies mutated or deleted in 50% or more probands for its syndrome) (MEN1, RET, CASR, CDC73) were identified for five syndromes. During stage 5 (1993 to the present), seven syndromal genes other than a principal gene were identified (CDKN1B, CDKN2B, CDKN2C, CDKN1A, GNA11, AP2S1, GCM2). Identification of AP2S1 and GCM2 became possible because of whole-exome sequencing. During stages 4 and 5, the newly identified genes enabled many studies, including robust assignment of the carriers and non-carriers of a mutation. Furthermore, molecular pathways of RET and the calcium-sensing receptor were elaborated, thereby facilitating developments in pharmacotherapy. Current findings hold the promise that more genes for HPT syndromes will be identified and studied in the near future. © 2018 American Society for Bone and Mineral Research.

[Genotype-phenotype correlations in multiple endocrine neoplasia type 2].

OBJECTIVE: To evaluate the relationship between different RET mutations and the aggressiveness of hereditary medullary thyroid cancer (HMTC) or the presentation of other endocrine disorders in patients with multiple endocrine neoplasia type 2 (MEN2). METHODS: A total of 73 thyroid medullary carcinoma patients from 22 Chinese kindreds who were treated in our center from 2010 to 2015 were enrolled. RET genes in the patients and their relatives were screened. RESULTS: According to the clinical data and 2015 American Thyroid Association (ATA) guidelines, patients were classified into 3 RET mutation risk groups: Modest, 24 cases; High, 48 cases; and Highest, 1 case. Multivariate analysis showed an increased likelihood of MTC stage III or IV at diagnosis with increasing of age and risk. The likelihood increased 11.6% per year of age at surgery (95% confidence interval, 1.040-1.198; P=0.002). The likelihood in patients with high risk was 7.9 times higher than patients with modest risk (95% confidence interval, 1.607-38.717; P=0.003). Aside from one patient with MEN2B, other 72 patients were MEN2A, of them, 28 cases from 7 kindreds with classical MEN2A (codon 634 & 618), 14 cases from 3 kindreds with cutaneous lichen amyloidosis (codon 634), 4 cases from 1 kindred with Hirschsprung's disease (codon 620), and 26 cases from 10 kindreds with familial MTC. CONCLUSION: The aggressiveness of HMTC and the presentation of other endocrine diseases are related to specific RET mutations. For RET mutation carriers, MTC and other endocrine diseases should be diagnosed and treated early based on the RET genotypes.

C-Cells and their Associated Lesions and Conditions: A Pathologists Perspective.

This paper updates the histopathology and cytopathology of thyroid tumors and proliferations derived from the para-follicular or C cells. Beginning with an historical over view, including the recognition of medullary thyroid carcinoma as a distinct histologic entity, its relationship to the hormone, calcitonin, (which was discovered in the same decade) and to thyroid C cells, medullary carcinoma and its variants are reviewed. The molecular biology of the tumors and the associated mutations in the tumors (somatic mutations) are discussed. Additionally the genetic features (germline mutations) including familial clusters and associations with other endocrine and neuroendocrine lesions are reviewed. Screening for the tumor and its precursors is included with a review of the latest American Thyroid Association guidelines for treatment as well as timing and approach to surgery. Tabular data of specific germline mutations and their relationships to tumor virulence, and prognosis are illustrated. Precursor and early C cell lesions such as C-cell hyperplasia and micro-medullary carcinoma are discussed. Difficulties and controversies in the definition of C-cell proliferations which are neoplastic and those which are "reactive" are reviewed. The entity of medullary microcarcinoma or medullary microcarcinoma is illustrated and the distinction between C cell nodules and microcarcinoma is defined using the latest available criteria. Finally the latest approved chemotherapeutic agents and their results in metastatic medullary thyroid carcinoma are included.

[Multiple endocrine neoplasia type 2]. / Zespól mnogiej gruczolakowatosci wewnatrzwydzielniczej typu 2.

Multiple endocrine neoplasia type 2 syndrome (MEN-2) is a rare hereditary cancer syndrome with autosomal dominant trait of inheritance. The most characteristic feature of this syndrome is a complete penetrance of medullary thyroid cancer. On the basis of differences in variable expression of pheochromocytomas, hyperparathyroidism, and other clinical features, MEN-2 is divided into three clinical variants, referred to as MEN-2A, MEN-2B and familial medullary thyroid cancer. In the most frequent variant, MEN-2A syndrome, apart from thyroid carcinoma, this syndrome includes also unilateral or bilateral pheochromocytoma and hyperparathyroidism. In less common MEN-2B, medullary thyroid cancer and pheochromocytoma occur together with complex nervous and skeletal abnormalities. Familial medullary thyroid cancer is a variant of MEN-2 in which individuals affected develop only this neoplasm without other manifestations of MEN-2. It is well known that MEN-2 is caused by mutations of different codons of the RET proto-oncogene. The identification of mutations associated with this syndrome has led to genetic testing to identify patients at risk for MEN-2. There is a significant genotype-phenotype correlation, which allows a more individualised approach to the timing of prophylactic thyroidectomy. In this paper, we review the current views on the etiopathogenesis, clinical presentation, diagnosis and treatment of MEN-2.

The relationship of cytomorphology of medullary thyroid carcinomas between family members with the same RET proto-oncogene mutation.

OBJECTIVE: To evaluate the relationship of the cytomorphology of medullary thyroid carcinomas (MTC) between family members with the same RET proto-oncogene mutation. STUDY DESIGN: Review of the fine-needle aspiration slides of 13 cases with MTC proven by surgery and pathology from 5 unrelated families with either multiple endocrine neoplasia (MEN) type 2A or familial MTC (FMTC). RESULTS: Small, round, and abundant large oval-to-polygonal cells were major cytomorphologic findings in 66.7% of family members with exon 11, codon 634 TGC → CGC germline mutation. Small, round cells and only a few or no polygonal cells were found in 66.7% of family members with exon 11, codon 634 TGC → TTC germline mutation and in 100% of family members with codon 634 TGC → TGG germline mutations, as well as in 100% of family members with exon 10, codon 620 TGC → GGC germline mutation. CONCLUSIONS: The high rate of similarity of cytomorphology (66.7-100%) in the family members with MEN type 2A or FMTC might be related to the same etiology in the production of MTC in the same family. The relationship of the respective cytomorphology with the long-term prognosis is worth elucidating further.

Update multiple endocrine neoplasia type 2.

Multiple endocrine neoplasia type 2 (MEN2) is a autosomal dominat inherited tumour-syndrome caused by germline activating mutations of the RET proto-oncogene on chromosome 10. It is clinically characterized by the presence of medullary thyroid carcinoma (MTC), bilateral pheochromocytoma and primary hyperparathyroidism (MEN2A) within a single patient. Three distinct clinical forms have been described depending on the phenotype: the classical MEN 2A, MEN 2B, an association of MTC, pheochromocytoma and mucosal neuroma, (FMTC) familial MTC with a low incidence of other endocrinopathies. Each variant of MEN2 results from different RET gene mutation, with a good genotype phenotype correlation. Genetic testing detects nearly 100% of mutation carriers and is considered the standard of care for all first degree relatives of patients with newly diagnosed MTC. Recommendations on the timing of prophylactic thyroidectomy and extent of surgery are based on a classification into four risk levels utilizing the genotype-phenotype correlations. MEN 2 gives a unique model for early prevention and cure of cancer and for stratified roles of mutation-based diagnosis of carriers.

Multiple endocrine neoplasia type 2 RET protooncogene database: repository of MEN2-associated RET sequence variation and reference for genotype/phenotype correlations.

Multiple endocrine neoplasia type 2 (MEN2) is an inherited, autosomal-dominant disorder caused by deleterious mutations within the RET protooncogene. MEN2 RET mutations are mainly heterozygous, missense sequence changes found in RET exons 10, 11, and 13-16. Our group has developed the publicly available, searchable MEN2 RET database to aid in genotype/phenotype correlations, using Human Genome Variation Society recommendations for sequence variation nomenclature and database content. The MEN2 RET database catalogs all RET sequence variation relevant to the MEN2 syndromes, with associated clinical information. Each database entry lists a RET sequence variation's location within the RET gene, genotype, pathogenicity classification, MEN2 phenotype, first literature reference, and comments (which may contain information on other clinical features, complex genotypes, and additional literature references). The MEN2 phenotype definitions were derived from the International RET Mutation Consortium guidelines for classification of MEN2 disease phenotypes. Although nearly all of the 132 RET sequence variation entries initially cataloged in the database were from literature reports, novel sequence variation and updated phenotypic information for any existing database entry can be submitted electronically on the database website. The database website also contains links to selected MEN2 literature reviews, gene and protein information, and RET reference sequences. The MEN2 RET database (www.arup.utah.edu/database/MEN2/MEN2_welcome.php) will serve as a repository for MEN2-associated RET sequence variation and reference for RET genotype/MEN2 phenotype correlations.

Hereditary medullary thyroid carcinoma: how molecular genetics made multiple endocrine neoplasia type 2 a paediatric disease.

Multiple endocrine neoplasia type 2 (MEN 2) is a genetic disorder associated with nearly 100% of lifetime risk of medullary thyroid carcinoma (MTC). MTC is the first tumour of the syndrome to manifest, it shows a nearly 100% penetrance and is the most common cause of death in patients with MEN 2. MEN 2A accounts for over 60-90% of patients with hereditary MTC and is characterized by a combination of MTC, pheochromocytoma and parathyroid adenoma. MEN 2B has a high risk of MTC, pheochromocytoma and includes additional clinical features such as mucosal neuromas, ganglioneuromatosis of the gastrointestinal tract, and a marfanoid habitus. Familial MTC, the third subtype of MEN 2, is characterized by MTC in the objective absence of adrenal and parathyroid gland involvement. The identification of the RET proto-oncogene as the susceptibility gene for MEN 2 has fundamentally changed diagnosis and treatment of the disease since 1993. Availability of genetic screening of at-risk children in MEN 2 kindreds made prophylactic thyroidectomy in asymptomatic mutation carriers possible and genotype-phenotype correlations led to codonoriented prophylactic surgery. In this context, MEN 2 has become a disease of the young child.

Management of patients with hereditary medullary thyroid carcinoma.

The heredity of medullary thyroid carcinoma within MEN2 syndrome is caused by heterozygous germline mutations in the RET proto-oncogene. Since MEN2-associated mutations involve only hot spots, the molecular genetic analysis of the RET proto-oncogene constitutes the perfect tool for the diagnosis of MEN2, being thus considered the standard method. The molecular genetic screening for MEN2-associated RET germline mutations should be carried out in all patients with an apparently sporadic medullary thyroid carcinoma or pheochromocytoma. This testing needs to include exons 10, 11, and 13 to 16 of the RET proto-oncogene. Such investigations are aimed at identifying an index person of a new MEN2 family. The detection of such a RET germline mutation is the basis for predictive molecular genetic testing within an affected family, and allows the exclusion or identification of gene carriers. For these family members at risk, prophylactic total thyroidectomy is recommended as a curative procedure, according to a risk-adapted, genetically based treatment algorithm. The management of such affected families should be always complemented by oncological and genetic counselling.

[Importance of endocrine imaging methods in multiple endocrine neoplasia type 2A proved by mutation analysis]. / Az endokrin szervek képalkotó vizsgálatának jelentösége mutációvizsgálattal igazolt multiplex endokrin neoplasia 2A típusának esete kapcsán.

Multiple endocrine neoplasias are rare, inherited disorders. The authors describe a case history of a patient with multiple endocrine neoplasia type 2A, who presented with unusual clinical manifestations. The diagnosis of phaeochromocytoma, which was the first manifestation of the disorder, was greatly facilitated with radiologic imaging methods. The authors review, on the basis of recent data from the literature, the importance of radiologic methods, which improved due to methodological advance. Finally, the authors emphasize the importance of follow-up for early diagnosis.

Multiple endocrine neoplasia type 1 and 2: from morphology to molecular pathology 1997.

Multiple Endocrine Neoplasia (MEN) is an inherited syndrome which appears in two major forms referred to as type 1 (MEN-1) and type 2 (MEN-2). MEN-1 is characterized by the occurrence of neuroendocrine parathyroid, pancreas, duodenum and pituitary lesions. In addition to these tumors adrenocortical, lipomatous and neuroendocrine tumors in other locations may develop. The genetic defect of MEN-1 has recently been identified and involves a new form of tumor suppressor gene called mu on chromosome 11q13. It codes for a protein called menin which is expressed in a variety of human tissues and organs. In MEN-1 gene carriers inactivating germline frameshift, nonsense, missense and in-frame deletion mutations scattered throughout the 10 coding exons have been identified. The MEN-2 syndrome is divided into three clinical variants referred to as MEN-2A, MEN-2B and familial medullary thyroid carcinoma (FMTC) which share medullary thyroid carcinomas as part of the disease phenotype. In MEN-2A pheochromocytomas and parathyroid hyperplasia and in MEN-2B additional skeletal abnormalities and ganglioneuromatosis may also be encountered. All three MEN-phenotypes are associated with oncogenic point mutations of the RET protooncogene on chromosome 10q11.2 which encodes a receptor-type tyrosine kinase. Its ligand--the glial cell line derived neurotropic factor (GDNF)--forms a signaling complex with the alpha type of the GDNF receptor. All neuroendocrine tumors of the different MEN-phenotypes may also occur sporadically and there are only few clinical and pathomorphological features which are helpful to discriminate sporadic from MEN-associated neuroendocrine neoplasms. The recent achievements of molecular pathology now allow for the unambiguous identification of MEN gene carriers among patients with neuroendocrine neoplasms by DNA testing for mutations in the mu and RET gene. In this overview, distinct macroscopic and histopathological features of the two MEN phenotypes will be summarized and most recent findings on the molecular pathology of these syndromes will be outlined, together with molecular methods to identify disease-gene carriers.

[Morphological typing, evaluation of tumor dignity and prognosis and etiologic classification of adrenomedullary and adrenocortical neoplasias]. / Morphologische Typisierung, Dignitts- und Prognose-beurteilung sowie ätiologische Einordnung adrenomedullärer und adrenokortikaler Neoplasien.

The aim of morphological tumour diagnosis is to answer clinical questions on type, biological potential, prognosis and aetiology of individual neoplasms. The limitations and perspectives of different methods used in the diagnosis of adrenal tumours, ranging from histology to molecular genetic DNA analyses, are described. When surgical specimens from adrenal neoplasms cannot be typed on the basis of histology and/or with clinica data (e.g., endocrine symptoms and history) as adrenocortical tumours, phaeochromocytomas or metastases to the adrenal, immunohistological investigations with a panel of different antibodies are necessary. After identification of the tissue derivation of an individual adrenal tumour, its biological potential must be assessed. Among adrenocortical neoplasms, adenomas and carcinomas can be distinguished by evaluation of various histological parameters (including structural features and signs of invasion) according to defined algorithms. In addition, conventional histology (by estimation of mitotic activity) allows the discrimination of tumours with especially high malignant potential from other adrenocortical carcinomas. In contrast, among adrenomedullary tumours even the combined use of histological, immunohistological and DNA cytophotometric techniques only allows the definition of risk groups (benign versus suggestive of malignancy), while reliable recognition of an individual malignant phaeochromocytoma is so far impossible. The question as to whether a particular phaeochromocytoma represents a sporadic tumour or a neoplasm inherited as one feature of a defined syndrome cannot be answered with the above methods, but only by the application of molecular genetic techniques.