Multiple endocrine neoplasia. Type IIa

Primary Hyperparathyroidism in Multiple Endocrine Neoplasia Type 2A in Denmark 1930–2021: A Nationwide Population-Based Retrospective Study

Studies of primary hyperparathyroidism (PHPT) in multiple endocrine neoplasia type 2A (MEN 2A) shows divergence in frequency, disease definition, reporting of clinical characteristics and traces of selection bias. This is a nationwide population-based retrospective study of PHPT in MEN 2A, suggesting a representative frequency, with complete reporting and a strict PHPT definition. The Danish MEN 2A cohort 1930-2021 was used. Of 204 MEN 2A cases, 16 had PHPT, resulting in a frequency of 8% (CI, 5-12). Age-related penetrance at 50 years was 8% (CI, 4-15). PHPT was seen in the American Thyroid Association moderate (ATA-MOD) and high (ATA-H) risk groups in 62% and 38% of carriers, respectively. Median age at PHPT diagnosis was 45 years (range, 21-79). A total of 75% were asymptomatic and 25% were symptomatic. Thirteen underwent parathyroid surgery, resulting in a cure of 69%, persistence in 8% and recurrence in 23%. In this first study with a clear PHPT definition and no selection bias, we found a lower frequency of PHPT and age-related penetrance, but a higher age at PHPT diagnosis than often cited. This might be affected by the Danish RET p.Cys611Tyr founder effect. Our study corroborates that PHPT in MEN 2A is often mild, asymptomatic and is associated with both ATA-MOD and ATA-H variants. Likelihood of cure is high, but recurrence is not infrequent and can occur decades after surgery.

The molecular pathogenesis of hereditary and sporadic adrenocortical and adrenomedullary tumors

Modern imaging modalities lead to frequent detection of adrenal masses, most of them incidental findings. Although the majority of adrenocortical and adrenomedullary tumors are benign, there are no reliable clinical and laboratory markers to distinguish most of them from malignant neoplasms. The molecular mechanisms underlying the pathogenesis of these tumors have recently begun to be unraveled. A fruitful avenue for the elucidation of tumorigenesis has been the study of adrenal tumors that are manifestations of hereditary or postzygotic genetic syndromes, because one knows the "first hit", i.e. the primary gene defect. In contrast, in sporadic adrenal tumors the first hit, possibly a somatic mutation of a tumor-related gene, is unknown, and therefore the sequence of genetic alterations is difficult to establish. In this article we review in addition to our own work the literature on molecular aspects of adrenocortical and adrenomedullary tumorigenesis.

Combining radioimmunotherapy and chemotherapy for treatment of medullary thyroid carcinoma: effectiveness of dacarbazine

BACKGROUND

To enhance the efficacy of chemotherapy for medullary thyroid carcinoma (MTC), we evaluated the effect of combining radioimmunotherapy (RAIT) with 90Y-anticarcinoembryonic antigen (CEA) monoclonal antibody MN-14 and chemotherapy in nude mice bearing human MTC xenografts. A preliminary study evaluated doxorubicin, dacarbazine (DTIC), cyclophosphamide, and vincristine, singly and in combination, for their effect on the growth of MTC xenografts (TT) in nude mice. Given individually, DTIC yielded the most effective tumor growth inhibition, delaying the mean time to doubling from 1 week for untreated tumor-bearing mice to 7.5 weeks. Administering either the 4 drugs in combination or a 2-drug combination comprised of doxorubicin and DTIC significantly improved the efficacy compared with any single drug alone, increasing the mean doubling time to 10-12 weeks.

METHODS

Drug doses were selected to conform to the doses of each drug given clinically. For the combined modality therapy, administration of 90Y-labeled anti-CEA monoclonal antibody MN-14 to nude mice bearing established TT tumors was followed by various chemotherapy regimens initiated 24 hours after RAIT. Chemotherapy protocols combined with RAIT included doxorubicin or DTIC alone and in combination, and the doxorubicin, DTIC, cyclophosphamide, and vincristine 4-drug protocol. Tumor volumes were measured weekly, and toxicity was evaluated by measuring blood counts and body weight.

RESULTS

Combinations of RAIT and chemotherapy with DTIC or RAIT and chemotherapy with the drug combinations were found to augment the antitumor effects of RAIT or chemotherapy alone, without a significant increase in toxicity. The mean tumor volume doubling times were increased up to 100% compared with the results of chemotherapy alone. No significant differences in tumor growth were observed between the RAIT plus DTIC protocol and the RAIT plus two- or four-drug protocols.

CONCLUSIONS

The superiority of the combined modality treatment argues for the integration of RAIT into chemotherapeutic regimens for MTC treatment. Clinical trials are needed to assess these principles in MTC patients.

Prognostic value of initial fasting serum gastrin levels in patients with Zollinger-Ellison syndrome

PURPOSE

To assess the value of the initial fasting serum gastrin (FSG) at presentation in patients with Zollinger-Ellison Syndrome (ZES) in predicting primary tumor characteristics and survival.

PATIENTS AND METHODS

A total of 239 patients were treated for ZES between December 1981 and September 1998, with a mean follow-up of 9.1 +/- 0.6 years. At initial evaluation, 86 patients (36%) had mild (0 to 499 pg/mL), 61 (25.5%) had moderate (500 to 1,000 pg/mL), and 92 (38.5%) had severe (> 1,000 pg/mL) elevations in FSG. Primary tumor location and size, presence of lymph node or hepatic metastases, and survival were analyzed based on the level of initial FSG.

RESULTS

In patients with sporadic ZES, but not in those with multiple endocrine neoplasia type 1 (MEN-1) and ZES, there was a significant relationship between the level of initial FSG and tumor size and location of primary tumor, frequency of lymph node and liver metastases, and survival. The median 5- and 10-year survival decreased with increasing initial FSG (P <.001) in patients with sporadic ZES; MEN-1 patients lived longer than sporadic ZES patients (P =.012), and survival in this group was not associated with the level of initial FSG. Multivariate analysis showed that factors independently associated with death from disease in patients with sporadic ZES were liver metastases (P =.0001), a pancreatic site (P =.0027), and primary tumor size (P =.011) but not initial FSG (P >.30).

CONCLUSION

The severity of FSG at presentation is associated with size and site of tumor and the presence of hepatic metastases, factors that are significant independent predictors of outcome. The level of FSG at presentation may be useful in planning the nature and extent of the initial evaluation and management in patients with sporadic ZES.

Familial medullary thyroid carcinoma (FMTC). Study of one family (treatment criteria)

AIM

The nosology of familial medullary thyroid carcinoma (FMTC) has been described as a distinct pathology, genetically determined and with autosomal dominant transmission with a gene penetrance of almost 100%. The diagnosis of this morbid condition can be made if at least four members of the same family are affected by calcitonin-secreting C-cell carcinoma.

METHODS AND RESULTS

We report the analysis of a family in which FMTC was diagnosed between 1993 and 1998. Of the five patients we confirmed as being affected by FMTC, we were able to perform a prophylactic thyroidectomy in only one case. The high possibility of lymph-node metastasis at the time of clinical diagnosis (52-75%), and the high morbidity and radio-chemo-resistance to adjuvant therapies, indicate total thyroidectomy with central lymph-node dissection.

CONCLUSION

It appears that preventive lymphadenectomy does not substantially improve survival, while pre-clinical diagnosis is of greater importance than surgery in improving survival and preventing recurrence. Total preventive thyroidectomy has been recommended in all carriers of ret genetic defects, even in families at risk with mutations of the 618 or 620 codon, because the penetrance of FMTC approaches 100%, and a 100% accordance between presence of the disease and gene carrier status is reported. This procedure would therefore represent the only possibility of achieving a 100% cure in subjects affected by familial medullary thyroid carcinoma.

Medullary carcinoma of the thyroid

Medullary thyroid cancer (MTC) is a distinct C-cell tumor of the thyroid. We review the oncogenesis and management of both sporadic tumors and those tumors arising as part of specific inherited syndromes. The RET proto-oncogene plays a role in the development of inherited forms of MTC and has become important in the clinical management of patients and their families. The recognition of the high rate of regional nodal involvement has led to lymphadenectomy being strongly considered for patients undergoing thyroidectomy for MTC.

Ret-proto-oncogene analysis in medullary thyroid carcinoma

INTRODUCTION

Medullary carcinoma of the thyroid (MTC) is a rare tumour which occurs in both sporadic and hereditary forms. Mutations of the RET proto-oncogene have been identified in hereditary forms. The aim of our study was to confirm or exclude familial disease by examining for germline mutations in the RET proto-oncogene in patients with medullary thyroid carcinoma.

METHODS

Nine patients with medullary thyroid carcinoma and 4 of their children were studied. Peripheral blood was used to examine for mutations in the RET proto-oncogene. When this was not available, archival thyroid tissue was used.

RESULTS

Seven patients had clinically sporadic tumours confirmed by mutational analysis of RET. Four children were at risk of being carriers of a mutated gene, as their fathers had histologically proven MTC and had tested positive for the mutation at codon 618 on exon 10 of the RET proto-oncogene. Three of these children carried the 618 mutation. To date, 2 have had a prophylactic thyroidectomy, the pathology of which revealed C-cell hyperplasia. One child had familial disease excluded by mutational analysis. One patient had a clinical diagnosis of MEN2B confirmed by detection of the 918 mutation on exon 16 of the RET proto-oncogene.

CONCLUSIONS

RET proto-oncogene analysis is a reliable method of differentiating familial from sporadic MTC. Mutational information determines which family members of affected kindreds are at risk of developing the disease and can be used to affect clinical management.

Multiple endocrine neoplasia type II and familial medullary thyroid carcinoma. Impact of genetic screening on management

The identification of ret protooncogene mutations in MEN-II and Hirschsprung disease has not only improved the clinical management of these genetic conditions but has also provided important information regarding mechanisms of transformation and neural crest development. An indication of how neural-crest cells migrate during embryonic life and the key processes involved in their differentiation now seems within reach. The continued pace of scientific discovery suggests that our understanding of and ability to prevent or treat hereditary and sporadic forms of MTC will continue to improve.

Surgical management of hyperparathyroidism in patients with multiple endocrine neoplasia type 2A

BACKGROUND

The surgical management of hyperparathyroidism in patients with multiple endocrine neoplasia type 2A (MEN 2A) is controversial. We report the long-term follow-up, mutational analysis, and surgical outcome in a large group of patients with MEN 2A and hyperparathyroidism.

METHODS

Clinical and genetic data for MEN 2A patients with biochemically and pathologically confirmed hyperparathyroidism and a minimum of 5 years of follow-up were analyzed retrospectively, and outcomes after surgical management were compared.

RESULTS

Thirty-five (29%) of 119 patients from 14 MEN 2A kindreds had biochemical and pathologic evidence of hyperparathyroidism, with a mean follow-up of 14.7 years. The phenotypic expression of hyperparathyroidism was associated with germline mutations of the RET protooncogene at codons 634 and 618. At initial operation, 21 (62%) patients had a selective resection, eight (24%) had a subtotal resection, five (14%) had total parathyroidectomy with autotransplantation, and one had an inadvertent total parathyroidectomy. Twenty-seven (77%) patients were cured by the first operation. Persistent hyperparathyroidism occurred in three (8.6%) patients, and recurrent hyperparathyroidism occurred in five (14.3%) patients; both occurred only in patients treated with selective or subtotal resection. Permanent postoperative hypoparathyroidism occurred in six (21%) of 29 patients after selective or subtotal resection, in the one patient with inadvertent total parathyroidectomy, and in one (20%) of 5 patients treated with total parathyroidectomy and autotransplantation.

CONCLUSIONS

Recurrent or persistent hyperparathyroidism occurs after selective or subtotal parathyroidectomy, as a result of either missed glands or interval development of neoplasia in previously normal parathyroid glands left in situ. Therefore we advocate total parathyroidectomy and heterotopic autotransplantation for patients with hyperparathyroidism and MEN 2A.

Secretory diarrhea in children: newly recognized toxins and hormone-secreting tumors

This review of bacterial toxins and hormones that stimulate diarrhea shows that we have learned much concerning the pathophysiology of these diarrheal states; however, we have much yet to learn. It is hoped that research will continue to enlighten us with regard to the pathophysiology, diagnosis, and treatment for these disease processes.

Application of genetic screening information to the management of medullary thyroid carcinoma and multiple endocrine neoplasia type 2

Application of RET proto-oncogene mutation analysis to the clinical management of MEN 2 and FMTC has simplified and enhanced the power of earlier used screening and treatment efforts for hereditary MTC. The approaches outlined herein are cost-effective, have improved diagnostic accuracy, and hold the promise of improved cure rates for this neoplasm. Further studies to elucidate the mechanism by which these activating mutations cause transformation may lead to other strategies for prevention or treatment of this neoplasm.

Clinical use of molecular information in the management of multiple endocrine neoplasia type 2A

One hundred and ninety-seven members of 28 kindreds with multiple endocrine neoplasia type 2A (MEN 2A) were screened for RET proto-oncogene exon 10 and 11 mutations. Seventy-one known affected individuals had mutations of codons 609, 618, 620 or 634, whereas 53 unaffected individuals had no abnormalities. Nineteen out of 54 individuals of unknown status, mostly children, had RET mutations. Four of these children had thyroidectomy based on this analysis and were found to have C-cell abnormalities. We identified one false negative mutation analysis because of a codon 691 polymorphism. We conclude that RET mutational analysis is a cost-effective and accurate method for determination of gene carrier status in MEN 2A.

Primary hyperparathyroidism in multiple endocrine neoplasia type 2A

The rarity of primary hyperparathyroidism (PHPT) in multiple endocrine neoplasia type 2A (MEN 2A) led us to study clinical findings, surgical therapy and outcome in 67 patients in order to evaluate our therapeutic strategy. The retrospective study was based on cases registered by the EUROMEN study group (nine participating centres) from 1972 to 1993. Characteristics of PHPT in 67 patients (41 females, 26 males) with MEN 2A were reviewed. All patients underwent exploratory neck surgery; PHPT was confirmed histologically and/or biochemically. The median age at diagnosis of PHPT was 38 years. In 75% of the patients, PHPT and medullary thyroid carcinoma were diagnosed synchronously, while in 4%. PHT was diagnosed earlier. In 18% of the patients, PHPT was diagnosed after thyroidectomy, and in 3%, after discovery of pheochromocytoma. Primary hyperparathyroidism was asymptomatic in 84% of the patients; 15% suffered from renal stones. Serum calcium was slightly elevated in 69% (2.9 +/- 0.2 mmol-1) and normal in 16% of subjects. A single adenomectomy was performed in 42% of the patients, subtotal parathyroidectomy in 31% and total parathyroidectomy with autotransplantation in 16%. Independent from the extent of resection, cure was achieved in 94% of the patients, including 13% with hypoparathyroidism; hypercalcaemia persisted in 3% and no information was available in 3%. In an 8-year follow-up, hypercalcaemia recurred in 12% of the patients, although half had undergone parathyroidectomy totally or subtotally. CONCLUSION. MEN 2A-related PHPT is characterized by a mild hypercalcemia which is mostly asymptomatic and can be cured by simple resection of an enlarged parathyroid gland in most cases.

RET proto-oncogene mutations in multiple endocrine neoplasia type 2 and medullary thyroid carcinoma

The identification of RET proto-oncogene mutations in patients with MEN2 2 years ago was a watershed event in the management of this genetic cancer syndrome. The identification of a finite number of mutations that together causes more than 95% of hereditary and 15-25% of sporadic MTC has made it possible to develop simple and definitive tests to screen individuals at risk for this tumour syndrome. The impact of this technology is enormous. It is now possible to reassure 50% of family members at risk that they, and their children, do not have to worry about developing MTC. In the other 50% who are gene carriers, it is now possible to approach clinical management with greater certainty and plot strategies that are likely to result in a greater percentage of curative therapy. It seems likely that this technology will also have an impact on the management of sporadic MTC, although it is still too early to define a specific role for mutational analysis in these patients, except to exclude hereditary disease. The identification of specific mutations causative for MTC makes it possible to conceive future strategies for the treatment or prevention of MTC and to further extend the impact of these exciting findings.

Medullary thyroid carcinoma

Medullary thyroid carcinoma accounts for 5-10 per cent of thyroid malignancies and occurs sporadically, and in three familial settings with autosomal dominant inheritance. Calcitonin, a 32 amino acid 3.5-kDa protein, is a biochemical marker of the tumour. Serum levels correlate with disease burden. Treatment initiated by screening allows disease removal at a premalignant phase: C cell hyperplasia. Genetic linkage studies locate the multiple endocrine neoplasia type 2A gene near the centromere of chromosome 10. Flanking genetic markers may allow polymorphic probes to examine DNA from a once-only blood sample to identify affected individuals. At what age thyroidectomy should be carried out in these patients is unclear.

Sipple syndrome with lichen amyloidosis as a paracrinopathy: pleiotropy, heterogeneity, or a contiguous gene?

A five-generation white family with multiple endocrine neoplasia type 2A had six affected members. Two, a mother and her daughter, had interscapular cutaneous pruritic lesions resembling macular/lichen amyloidosis. In the daughter, light microscopy showed homogeneous aggregates in the papillary dermis. Crystal violet staining showed metachromasia and indicated that the deposits were amyloid. This is the fourth family with familial medullary thyroid carcinoma with cutaneous amyloidosis and as such it allowed comparative analysis. Genetic heterogeneity, a contiguous gene, and pleiotropy were considered. It appears that multiple endocrine neoplasia type 2A/familial medullary thyroid carcinoma with cutaneous amyloidosis represents the phenotypic variability of the expression of a pleiotropic gene. The condition is one of the predominantly ectodermal autosomal dominant phakomatoses and is most likely a paracrinopathy.

Medullary carcinoma of the thyroid: current diagnosis and management

Medullary thyroid carcinoma (MTC) accounts for 5-10% of thyroid malignancies and occurs in either a sporadic or a familial form. The familial form is inherited in an autosomal dominant pattern, and expressed clinically as multiple endocrine neoplasia (MEN), types IIa and IIb, or as familial MTC alone. This neoplasm is derived from the parafollicular or C-cells, and has the ability to secrete a variety of polypeptide hormones including calcitonin, which serves as a tumor marker for the presence of MTC. The development of a calcitonin radioimmunoassay and the screening of patients at risk for the familial forms of MTC allows the diagnosis of the neoplasm in an occult stage when total thyroidectomy results in virtually 100% cure. We will present our experience with the diagnosis, treatment, and postoperative follow-up of our patients with this interesting neoplasm.

The impact of gene mapping techniques on the management of multiple endocrine neoplasia type 2

There has been sustained progress toward the identification of the gene for multiple endocrine neoplasia type 2. Closely linked and flanking DNA markers have been identified, and it is now possible to assign gene carrier status in informative families at risk with a >90% certainty by the use of molecular genetic techniques. Application of-these techniques, however, requires an understanding of their current limitations and caution in their use of clinical decision making.

Medullary carcinoma of the thyroid: management of persistent hypercalcitonaemia utilizing [99mTc] (v) dimercaptosuccinic acid scintigraphy

Whole body scintigraphy with [99mTc] (v)dimercaptosuccinic acid (pentavalent DMSA) was performed in seven patients with histologically confirmed medullary carcinoma of the thyroid (MCT). Six of these patients had undergone previous thyroid resections for MCT and, although asymptomatic at the time of pentavalent DMSA scintigraphy, had persistent and serial elevations in their plasma calcitonin levels. One additional patient was scanned before and after total thyroidectomy for MCT. The pentavalent DMSA scintigram demonstrated either local neck recurrence (three patients) or distant metastases (two patients) in five of the six asymptomatic patients. In one asymptomatic patient only equivocal neck uptake was demonstrated. Since he had only minimal calcitonin elevations, repeat neck exploration was not performed. The one patient studied before thyroid resection for MCT demonstrated neck uptake before, but not after, total thyroidectomy. The results of the scintigrams had significant impact on patient care and resulted in neck re-exploration (three patients), neck biopsy (one patient), and lumbar spine biopsy and subsequent radiotherapy (one patient). These data demonstrate pentavalent DMSA to be a sensitive localizing agent in the evaluation of asymptomatic MCT patients with hypercalcitonaemia. Accurate targeting of treatment may be shown in due course to have a beneficial impact on survival.

Long-term follow-up of a kindred with multiple endocrine neoplasia type IIA

A kindred with multiple endocrine neoplasia type IIA was studied. In four of five fully documented cases, patients presented with adrenal medullary disease during the second or third decade; in three cases, medullary thyroid carcinoma was not diagnosed until the fourth decade. This kindred seems to have an aggressive variant of adrenal medullary disease in which clinical presentation is early, metastasis occurs, and oncological cure is uncommon. Early detection and operation were important, and symptoms were controlled with operations and alpha- and beta-adrenergic blockade in uncured members.

Advances in the diagnosis and treatment of medullary thyroid carcinoma

Medullary thyroid carcinoma accounts for 5 to 10 per cent of all thyroid malignancies and may occur in a familial or a sporadic pattern. This article reviews the authors' experience with 200 patients with medullary thyroid carcinoma and outlines the recent advances made in our understanding of the biochemical properties of these cancer cells and the relationship of different tumor markers to prognosis.