Management of hyperparathyroidism (PHP) in MEN2 syndromes in Europe

Two sisters diagnosed with familial paraganglioma syndrome type 1 (FPGL1) and multiple endocrine neoplasia type 2A (MEN2A)

BACKGROUND

In clinical practice, genetic testing has become standard for many cancerous diseases. While a diagnosis of a single hereditary syndrome is not uncommon, the coexistence of two genetic diseases, even with partially common symptoms, remains unusual. Therefore, targeted next-generation sequencing (NGS), along with genetic consultation and imaging studies, is essential for every patient with confirmed paraganglioma. In this report, we present two sisters diagnosed with multiple endocrine neoplasia type 2 (MEN2A) and familial paraganglioma syndrome type 1 (FPGL1).

CASE PRESENTATION

After presenting to the clinic with neck tumors persisting for several months, both patients underwent tumor removal procedures following imaging and laboratory studies. Pathological reports confirmed the diagnosis of paragangliomas. Subsequently, genetic testing, including NGS, revealed a mutation in the rearranged during transfection (RET) gene: the heterozygous change (c.2410G > A), (p.Val804Met), and a variant of the succinate dehydrogenase complex subunit D (SDHD) gene: (c.64 C > T), (p.Arg22Ter). Subsequently, thyroidectomy procedures were scheduled in both cases.

CONCLUSION

To the best of our knowledge, this is the first report presenting these two mutations in two related patients, resulting in distinctive genetic syndromes with similar manifestations. This underscores that although infrequent, multiple hereditary disorders may co-occur in the same individual.

Multiple endocrine neoplasia type 2: A reveiw

Multiple endocrine neoplasias are rare hereditary syndromes some of them with malignant potential. Multiple endocrine neoplasia type 2 (MEN 2) is an autosomal dominant hereditary cancer syndrome due to germline variants in the REarranged during Transfection (RET) proto-oncogene. There are two distinct clinical entities: MEN 2A and MEN 2B. MEN 2A is associated with medullary thyroid carcinoma (MTC), phaeochromocytoma, primary hyperparathyroidism, cutaneous lichen amyloidosis and Hirschprung's disease and MEN 2B with MTC, phaeochromocytoma, ganglioneuromatosis of the aerodigestive tract, musculoskeletal and ophthalmologic abnormalities. Germline RET variants causing MEN 2 result in gain-of-function; since the discovery of the genetic variants a thorough search for genotype-phenotype associations began in order to understand the high variability both between families and within family members. These studies have successfully led to improved risk classification of prognosis in relation to the genotype, thus improving the management of the patients by thorough genetic counseling. The present review summarizes the recent developments in the knowledge of these hereditary syndromes as well as the impact on clinical management, including genetic counseling, of both individual patients and families. It furthermore points to future directions of research for better clarification of timing of treatments of the various manifestations of the syndromes in order to improve survival and morbidity in these patients.

MEN 2A syndrome - Multiple endocrine neoplasia with autosomal dominant transmission

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Every case essential, because MEN 2A is reported in 500–1000 families worldwide.

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This case reflects correct clinical steps in avoidance of possible complications.

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It contributes to the existing limited literature reports.

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MTC can be confirmed before macroscopic changes through evaluation of calcitonin.

Introduction

Multiple endocrine neoplasias (MEN) are rare inherited syndromes. MEN type 2 syndromes occur in 1:30000 individuals, and are reported in approximately 500–1000 families worldwide, the most frequent being MEN 2A (80%), followed by familial medullary thyroid carcinoma (15%) and MEN 2B (5%) (Marx and Wells, 2011; Dumitrache, 2012).

Case

The patient, a 20-years old with MEN 2A syndrome, which has been manifested by bilateral pheochromocytoma and medullary thyroid carcinoma. It was a familial form, having first degree relatives (mother) with pheochromocytoma. The patient underwent laparoscopic adrenalectomy on her left in 2015, laparoscopic adrenalectomy on the right in 2019 and total thyroidectomy in 2020 year. The postoperative evolution of this patient is favorable. She is satisfied with the received treatment and is being supervised by an endocrinologist, undergoing hormone replacement therapy.

Conclusions

The case demonstrates the importance of the radical approach to MEN 2A syndrome from both a therapeutic and surgical point of view.

If a pheochromocytoma is detected, adrenalectomy should be performed before thyroidectomy or other surgery to avoid intraoperative catecholamine release.

Laparoscopy is the choice of approach in surgical treatment. Limitations only arise because of technical difficulties or tumor size.

Primary hyperparathyroidism presenting with acute pancreatitis and asymptomatic bone involvement

A 15-year-old female patient presented to the emergency room with vomiting and abdominal pain. She had two similar attacks in the previous three months both of them were diagnosed as pancreatitis in two different hospitals. On admission, her serum calcium and parathyroid hormone levels were very high. CT scan revealed left inferior parathyroid adenoma. Investigations to rule out possible multiple endocrine neoplasia were all negative. The patient was managed by intravenous fluids and furosemide to lower her serum calcium level. Then, left inferior parathyroidectomy was done. Postoperatively, the patient had hungry bone syndrome with severe hypocalcaemia and was managed by intravenous calcium infusion for five days in the intensive care unit. Later, she was kept on oral calcium and vitamin D supplementation. She became symptom-free and her serum calcium improved gradually.

Primary Hyperparathyroidism in MEN2 Syndromes

One of the components of trethe classical form of MEN2 syndromes is primary hyperparathyroidism (PHP). It occurs in 20-30% of the typical MEN2A syndrome. The prevalence is more rare in gene carriers as these frequently have familial MTC only. PHP is diagnosed more frequently in association with the exon 11, codon 634 mutation of the ret gene-so there is phenotype/genotype correlation. The clinical manifestations of PHP in MEN2 are usually mild and the peak age of diagnosis after the 3rd decade. The treatment is surgical excision of the enlarged gland(s). Although there can be multigland disease in the parathyroids, it is frequently the case that both hyperplasia and adenoma may coexist, or even a single adenoma may be found during the investigation and finally during the operation. Patients with MEN2 syndromes should be screened for PHP with serum calcium measurements. The intensity of the screening should be higher in those carrying the ret mutations most frequently associated with this manifestation.