Familial endocrine tumors; report of two unrelated kindred affected with pheochromocytomas, one also with multiple thyroid carcinomas

Medullary thyroid carcinoma: a narrative historical review

INTRODUCTION

Sporadic or hereditary medullary thyroid carcinoma (MTC) is an uncommon thyroid malignancy arising from calcitonin secreting parafollicular C cells. Interestingly, MTC and calcitonin were distinct entities that were discovered independently yet concurrently, and their association was unknown.

AREAS COVERED

This review aims to present a historical review of the evolution of our understanding of MTC and its tumor marker calcitonin to highlight the prominent individuals that influenced and shaped our knowledge of this uncommon thyroid cancer type up to the dawn of the 21^st century. An overview of all published reports of novel research and work summarizing important findings for MTC and calcitonin was carried out.

EXPERT OPINION

Surgery remains the cornerstone of treatment for localized MTC. However, several new treatment options are either available or in development for advanced or metastatic MTC, including several novel small molecules targeting oncogenic RET and peptide receptor radionuclide therapy, immunotherapy, radioimmunotherapy, and radiofrequency ablation. In the near future, these novel treatments hold promise for therapy of this very distinct thyroid cancer type.

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.

15 YEARS OF PARAGANGLIOMA: Pheochromocytoma, paraganglioma and genetic syndromes: a historical perspective

The last decades have elucidated the genetic basis of pheochromocytoma (PC) and paraganglioma (PGL) (PCPGL)-associated hereditary syndromes. However, the history of these syndromes dates back at least another 150 years. Detailed descriptions by clinicians and pathologists in the 19th and 20th centuries led to the recognition of the PCPGL-associated syndromes von Hippel-Lindau disease, neurofibromatosis type 1, and multiple endocrine neoplasia type 2. In the beginning of the current millennium the molecular basis of the hereditary PGL syndrome was elucidated by the discovery of mutations in genes encoding enzymes of the Krebs cycle, such as succinate dehydrogenase genes (SDHx) and other mutations, causing 'pseudo-hypoxia' signaling. These recent developments also marked a paradigm shift. It reversed the traditional order of genetic research that historically aimed to define the genetic basis of a known hereditary syndrome but now is challenged with defining the full clinical phenotype associated with a newly defined genetic basis. This challenge underscores the importance to learn from medical history, continue providing support for clinical research, and train physicians with regards to their skills to identify patients with PCPGL-associated syndromes to extend our knowledge of the associated phenotype. This historical overview provides details on the history of the paraganglial system and PCPGL-associated syndromes. As such, it hopefully will not only be an interesting reading for the physician with a historical interest but also emphasize the necessity of ongoing astute individual clinical observations and clinical registries to increase our knowledge regarding the full phenotypic spectrum of these conditions.

Standards of care intended for multiple endocrine neoplasia families

In the past, the medical expenditure for multiple endocrine neoplasia families was high and the course of their disease not predictable. In a couple of decades, the prospects changed completely. The genetic origin of the diseases is well known and prevention is possible, whereas in advanced stages target-directed treatment is coming within reach. The most important change is the responsibility for these families. Initially, this was completely the task of the attending physician, whereas at this moment patients and disease gene carriers themselves have the central responsibility with respect to these diseases. Unfortunately, for them information about the disease is insufficiently available.

Hereditary hyperparathyroidism syndromes

Primary hyperparathyroidism is a common endocrine disorder, resulting from a persistent hypercalcemia along with an inadequate secretion of parathyroid hormone. In approx 95% of cases, it occurs sporadically; rarely, it is part of familial syndromes. These inherited syndromes typically present at an earlier age than the nonheritable form and occur with equal frequencies in both sexes. The differential diagnosis is often difficult, but it is of fundamental importance for the management of patients and their family. The availability of specific genetic tests has improved the diagnostic accuracy allowing early diagnosis in asymptomatic family members. Before the advent of genetic testing, a definitive diagnosis could be made only in symptomatic cases based on clinical data and family history.

Management of medullary thyroid carcinoma and MEN2 syndromes in childhood

Medullary thyroid carcinoma (MTC) and the multiple endocrine neoplasia (MEN) type 2 syndromes are rare but important endocrine diseases that are increasingly managed by pediatric providers. MTC is generally associated with a favorable prognosis when diagnosed during childhood, where it frequently occurs secondary to activating mutations in the RET proto-oncogene and arises from pre-existing C-cell hyperplasia. MEN2A accounts for 90-95% of childhood MTC cases and is most commonly due to mutations in codon 634 of RET. MEN2B is associated with the most aggressive clinical presentation of MTC and is almost always due to the Met918Thr mutation of RET. Surgery is the primary treatment and only chance of cure, although the advent of targeted therapies seems to be improving progression-free survival in advanced cases. Since the discovery of the role of RET in MEN2A, considerable advances in the management of this syndrome have occurred, and most of the children with MEN2A who have undergone early thyroidectomy will now lead full, productive lives. Strong genotype-phenotype correlations have facilitated the development of guidelines for interventions. Contemporary approaches for deciding the appropriate age at which surgery should take place incorporate data from ultrasonography and calcitonin measurements in addition to the results of genotyping. To optimize care and to facilitate ongoing research, children with MTC and the MEN2 syndromes are optimally treated at tertiary centers with multidisciplinary expertise.

Hyperparathyroid genes: sequences reveal answers and questions

OBJECTIVE

To review hyperparathyroid syndromes and genes.

METHODS

Pertinent original studies from the literature are discussed.

RESULTS

Six main hyperparathyroid syndromes are recognized; 5 are from germline mutations in 4 genes-CASR, MEN1, RET, and HRPT2. Each hyperparathyroid syndrome was first described around 1965; the main gene for each syndrome was identified about 30 years later. Gene identification addressed clinical issues. (1) Testing for mutation carriers among affected probands or among unaffected relatives is more robust than prior methods, which were based on syndromal traits such as serum calcium. (2) Interpreting a gene test (RET) could guide an important intervention; other gene tests could yield useful information for patients and physicians. (3) Proving the roles of each gene (in particular, MEN1 somatic mutations) provided insights about contributions to many common tumors. (4) Clarifying molecular pathways and drugs led, for example, to the CASR-aided development of calcimimetic and calcilytic drugs. (5) Explaining novel features, such as the CASR gene encoding a membrane calcium-sensing receptor and its mutations resulting in nonsuppressed parathyroid hormone secretion uncoupled from proliferation, characterized familial hypocalciuric hypercalcemia. (6) Disclosing probands without an identifiable mutation promoted searches for other syndromal genes. Subsequently, rare multiple endocrine neoplasia type 1-like families were shown to have inactivating germline mutations, first of p27 and subsequently of p15, p18, or p21.

CONCLUSION

The next frontier in mutation detection is arriving, with possible sequencing of the whole exome or even the whole genome for 1 case or 1 tumor at an affordable cost.

First description of parathyroid disease in multiple endocrine neoplasia 2A syndrome

Hyperparathyroidism and/or parathyroid hyperplasia, medullary thyroid carcinoma (MTC), and pheochromocytomas compose the hallmarks of the multiple endocrine neoplasia type 2A (MEN 2A) syndrome. Revisiting a report in 1939 of a patient with hyperparathyroidism and parathyroid hyperplasia led to a search for evidence of MEN 2A. From medical records and discussion with family members, longitudinal follow-up of the patient and her descendants was obtained. Molecular diagnostics were integrated in the care of subsequent generations. The literature on hyperparathyroidism and MEN 2A was reviewed. Children of the proband exhibited all components of MEN 2A and the RET mutation of 634 TGC>CGC. The pedigree was typical for this mutation. Papers on anthropologic studies demonstrate skeletal evidence of hyperparathyroidism in humans centuries ago. The initial report of the proband preceded the publications defining both MTC and MEN 2A. The values of in-depth family histories and genetic analyses are exemplified.

Medullary Thyroid Carcinoma

Medullary thyroid carcinoma is a neuroendocrine tumor derived from the C cells of the thyroid gland and accounts for approximately 5% of all thyroid carcinomas. Approximately 30% of the cases are associated with an autosomal dominant syndrome called multiple endocrine neoplasia type 2, and the identification of these individuals is important because affected family members may benefit from an early diagnosis. The treatment of this disease is predominantly surgical, and the impact of radiotherapy and chemotherapy is limited. The identification of the associated molecular events has lead to the development of specific molecular targeted agents that may change the way this disease is treated in the near future.

Familial Multiple Endocrine Neoplasia

In 1903, Erdheim described the case of an acromegalic patient with a pituitary adenoma and three enlarged parathyroid glands. Fifty years later, Underdahl et al reported 8 patients with a syndrome of pituitary, parathyroid, and pancreatic islet adenomas. In 1954, Wermer found that the syndrome was transmitted as a dominant trait. In 1959, Hazard et al described medullary (solid) thyroid carcinoma (MTC), a tumor that later was found to be a component of two endocrine syndromes. The first of these described by Sipple in 1961 comprised pheochromocytoma, MTC, and parathyroid adenoma. The second, described by Williams et al in 1966, was the combination of mucosal neuromas, pheochromocytoma, and MTC. In 1968, Steiner et al introduced the term "multiple endocrine neoplasia" (MEN) to describe disorders featuring combinations of endocrine tumors; they designated the Wermer syndrome as MEN 1 and the Sipple syndrome as MEN 2. In 1974, Sizemore et al concluded that the MEN 2 category included two groups of patients with MTC and pheochromocytoma: one with parathyroid disease and a normal appearance (MEN 2A) and the other without parathyroid disease but with mucosal neuromas and mesodermal abnormalities (MEN 2B). Later, additional nonendocrine conditions (von Recklinghausen neurofibromatosis and von Hippel-Lindau disease) were found accompanying other more recently described familial MEN syndromes, indicating that these diseases are very complicated disorders.

[Usefulness of RET proto-oncogene in the diagnosis of hereditary-type medullary carcinoma of the thyroid. Correlation with surgical findings]

In about 25% of cases medullary thyroid carcinoma (MTC) is hereditary. In this group is possible to detect germline point mutations of the RET proto-oncogene in about 95% of the studied cases. The purpose of the present paper is to confirm the value of the RET in the screening of the hereditary MTC. We studied 43 subjects at risk for a Multiple Endocrine Neoplasia Type 2A Syndrome. RET analysis was positive for MEN 2A in 22 subjects. Fifteen of the 22 have undergone a total thyroidectomy at our facility. Histopathological study of the surgical specimens confirmed the presence of a MTC in all the cases. According with our experience. RET analysis is a 100% sensitive and specific method of hereditary MTC screening, and we think it has obvious advantages over the calcitonin tests in technical, economic and ethic aspects.

Utility of RET mutation analysis in multiple endocrine neoplasia type 2

OBJECTIVE

To review the role of RET mutation analysis in the diagnosis of multiple endocrine neoplasia type 2 (MEN 2) and in presymptomatic screening for this disorder.

DATA SOURCES

Review of the medical literature and current clinical practice.

CONCLUSIONS

RET mutation analysis is a sensitive and specific test for MEN 2. It plays a pivotal role in the diagnosis and management of patients and families with MEN 2 and in the individual who presents with an apparently sporadic medullary thyroid carcinoma or pheochromocytoma. These disorders may first come to the attention of either the anatomic or clinical pathologist, who has the opportunity to see that appropriate testing is done. As with any familial disease, professional genetic counseling is an important part of the care of these patients.

A REVIEW OF 17 CASES OF CARCINOMA OF THE THYROID AND PHAEOCHROMOCYTOMA

The salient features of 15 cases of carcinoma of the thyroid and phaeochromocytoma taken from the literature and two personal cases are reviewed. The significant points noted are the frequency with which the adrenal tumours were bilateral, the frequency with which a family history of phaeochromocytoma (six cases) and thyroid carcinoma (four cases) was present, and the frequency with which the type of thyroid tumour was medullary carcinoma. In four of the 15 published cases the thyroid tumour was described as being medullary. Two personal cases both had medullary carcinoma of the thyroid, and this was also the type of thyroid carcinoma present in five of the published cases in which the thyroid histology was personally reviewed, making a total of 11 medullary carcinomas out of 17 cases. At least one other tumour was probably medullary, judging by the histological description. It is suggested that the association between phaeochromocytoma and thyroid carcinoma is specifically with medullary carcinoma of the thyroid. Both personal cases showed multiple neural tumours; and because of this and the association with phaeochromocytoma the possible neural origin of medullary carcinoma of the thyroid is briefly discussed. The occurrence in a few cases of parathyroid tumours has raised the possibility that these cases are related to the multiple endocrine adenoma syndrome. The dissimilarity between the cases with medullary carcinoma of the thyroid and phaeochromocytoma and those cases with ademonas involving pituitary, parathyroid, adrenal cortex and pancreatic islets is stressed. The term ;medullary tumour syndrome' is suggested as a convenient non-committal name for this association of medullary carcinoma of the thyroid with tumours of the adrenal medulla.

Dominant familial syndromes with endocrine hyperfunction: An additional syndrome?

At least 8 separate dominant syndromes have been described which have hyperfunctioning endocrine tumors as an important component. Scattered reports in the literature suggest that there may be an additional syndrome, in which extra-adrenal paragangliomas (often multiple), pituitary adenomas, and parathyroid hyperplasia coexist. Of 3 such cases described to date, 2 have included information about the family history, which in each case suggested dominant inheritance. This would presumably be a less common syndrome than the others recognized previously, so that full evaluation of endocrine findings and family history in future cases will be important for developing our understanding of the syndrome.

Multiple endocrine neoplasia

The MEN syndromes continue to be the focus of considerable interest and research. Since successful treatment requires early diagnosis, proper screening and follow-up of patients at risk is important. In the individual at risk for developing MEN IIa, annual screening should include measurement of the basal and stimulated plasma CT levels, and determination of plasma levels of calcium, PTH, and CEA. Twenty-four hour urine excretion rates of norepinephrine, epinephrine, metanephrine, dopamine, and VMA should also be obtained. It is our recommendation that this screening be continued through the third decade of life. Patients having thyroidectomy for MTC need to be tested annually for recurrent MTC and the development of adrenal medullary disease. All patients at risk for developing MEN IIb should be evaluated in a similar fashion. Recently, several groups using DNA linkage analysis have mapped the gene for MEN IIa to chromosome 10, although the exact location of the gene is yet to be determined. Preliminary linkage studies have mapped the gene for MEN I to chromosome 11. The identification of the genes for MEN I and MEN II will greatly simplify the diagnosis of the disease and perhaps also the therapy of affected patients.

Phaeochromocytoma and acute cardiovascular death (with special reference to myocardial infarction)

The causes of death, as determined by autopsy, in 10 patients dying from the acute effects of phaeochromocytoma were myocardial infarction (five patients), left ventricular failure (two patients), cerebral haemorrhage (two patients) and circulatory collapse with malignant phaeochromocytoma (one patient). Most patients died shortly after admission during the course of a fulminant cardiovascular illness and the underlying tumour was unsuspected in eight instances. The clinical features and post-mortem cardiovascular findings are reviewed.

Multiple endocrine neoplasia syndromes

The multiple endocrine neoplasia (MEN) syndromes are characterized by autosomal dominant inheritance with a high degree of penetrance but varying expression. This review gives a classification of these syndromes and a short summary of the historical background. The pathogenesis of the disease and its possible origin in the APUD cell system are discussed together with the mechanisms underlying normal and ectopic hormone production by MEN tumors on the basis of recent findings in molecular endocrinology. The natural history and the clinical manifestations of the different syndromes are described. The sensitivity and discriminative capacity of the tests used to detect the syndromes in an early stage are compared. The choice of therapy and criteria for the timing and extensiveness of treatment are also considered. Lastly, problems associated with the ethical and legal aspects of screening, central registration, and monitoring of relatives at risk are described.

Calcitonin, somatostatin and ACTH immunoreactive cells in a case of familial bilateral thyroid medullary carcinoma

Bilateral medullary carcinoma of the thyroid (MCT) was discovered in a symptomless patient of a high-risk MCT family. Raised serum calcitonin responding abnormally to pentagastrin led to a thyroidectomy. Grossly, the thyroid showed one nodule in the upper third of each lobe. Light microscopy revealed typical MCT with amyloid deposits. Nontumoral thyroid tissue showed C cell parafollicular hyperplasia. Electron microscopy detected intracellular secretory granules (mean diameter, 150 nm) and typical amyloid fibrills. Immunochemistry revealed numerous calcitonin immunoreactive cells in the nodules, in normal para and intrafollicular C-cells and hyperplastic C-cells. Somatostatin and ACTH were detected in certain tumor cells, but not in normal and hyperplastic C-cells. MCT hormonal production potential is discussed.

Familial testicular teratoma in 2 children: familial report and review of the literature

Familial occurrence of a testicular tumor is rare. We report mature teratomas in 2 first cousins in a consanguineous family. The cases were unique because both tumors were pathologically similar and their onsets were close. Of 34 families with testicular neoplasms reviewed this is the first family composed of 2 affected children with mature teratomas. The analysis of the familial cases showed segregation of twins and a slightly higher incidence of bilateral tumors. The genetic roles are discussed in the etiology of testicular tumor.

Pituitary adenoma, primary parathyroid hyperplasia and papillary (non-medullary) thyroid carcinoma. A case of multiple endocrine neoplasia (MEN)

An acidophilic pituitary adenoma associated with primary nodular parathyroid hyperplasia and a small papillary thyroid carcinoma was discovered at the autopsy of a 44 year old female acromegalic. The thyroid carcinoma showed evidence of lymphatic spread. Several etiopathogenetic mechanisms for the non-medullary thyroid carcinomata associated with Multiple Endocrine Neoplasia (MEN) have been postulated, since the follicular epithelium of the thyroid does not belong to the neural ectoderm derivates unlike the C-cells of the thyroid, the adenohypophysis and probably the parathyroid glands. Apart from genetic influence, or coincidence, one has to rule out carcinogenic exposure or hormonal influence. Clinically speaking, one should always consider whether malignant thyroid disease coexists with hyperplastic or neoplastic parathyroid tissue.

Familial islet-cell adenomatosis

Familial multiple adenoma of pancreatic beta-cells is described for the first time. The occurrence of diabetes mellitus in different members of the family raises the possibility of a common genetic origin for the multiple islet-cell adenomas and the diabetic trait. The evidence suggests that this gene is autosomal and dominant, that it is not linked with the HLA antigens, and that is causes an abnormal sensitivity of the beta-cells, which become hyperplastic or hypofunctional.

Familial medullary carcinoma of the thyroid through 3 generations

A family with high genetic penetrance of medullary carcinoma of the thyroid was reported. Seven proven (6 patients and one autopsy case) and 2 probable cases of medullary carcinoma were present in 25 members through 3 generations. An endogemy had intervened in the prior generation of these cases. Preliminary results in clinicopathological examinations of 7 proven cases were as follows; clinically, all of the cases showed B type blood group. Glycosuria was found in 2 cases, and diarrhea in one case. Serum thyrocalcitonin being estimated in two cases showed high levels. The autopsy cases coexisted with medullary carcinoma of the thyroid and pheochromocytoma of the right adrenal. Pathologically, the majority of tumors occurred in both thyroid lobes, and were present from the middle to upper portion of the thyroid. The tumor showed a variety of histological features even in the same tumor. In the tumor cell, numerous membrane-limited granules were seen with an electron microscope. Amyloid was demonstrated only in the tumor tissue.

Medullary carcinoma of the thyroid with parathyroid adenoma and hypercalcaemia

A patient with hyperparathyroidism due to a parathyroid adenoma was found to have metastatic medullary carcinoma in lymph nodes close to the thyroid gland. The finding of normal calcitonin and parathormone concentrations after removal of the adenoma suggested that the parathyroid lesion was not the result of the hypocalcaemic action of calcitonin produced by the tumour in the thyroid. Seventeen other examples of the association between medullary carcinoma and parathyroid enlargement are briefly reviewed.The pathogenesis of the parathyroid lesions is discussed, and it is suggested that some may be caused by the hypocalcaemic action of calcitonin, while others may be part of a syndrome of multiple endocrine adenomatosis.

Pheochromocytomata: analysis of cardiovascular symptomatology, preoperative diagnostic procedure, surgical approach and the genetic aspect and report of five cases

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Familial medullary carcinoma of the thyroid

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