Multiple endocrine neoplasia type 2 (MEN 2)

Genetics and imaging of pheochromocytomas and paragangliomas: current update

Pheochromocytomas (PCCs) and paragangliomas (PGLs) are rare, heterogeneous neuroendocrine neoplasms of the autonomous nervous system of chromaffin cell origin that may arise within the adrenal medulla (PCCs) or the sympathetic and parasympathetic paraganglia (PGLs). Currently referred to by the umbrella term pheochromocytomas-paragangliomas (PPGLs), these distinct tumors are characterized by specific histopathology as well as biological and clinical profiles. PPGLs may occur as part of hereditary syndromes (40% of cases) or as sporadic tumors. Currently, there are 12 different hereditary syndromes with characteristic genetic abnormalities, at least 15 well-characterized driver genes and distinct tumor metabolic pathways. Based on the Cancer Genome Atlas (TCGA) taxonomic schemata, PPGLs have been classified into three main clusters of specific genetic mutations and tumor pathways with clinical, biochemical, and prognostic implications. Imaging plays a pivotal role in the initial diagnosis, tumor characterization, evaluation of treatment response, and long-term surveillance. While MDCT and MRI help in the anatomic localization, SPECT, and PET using different radiotracers are crucial in the functional assessment of these tumors. Surgery, chemotherapy, and radiotherapy are currently available treatment options for PPGLs; antiangiogenic drugs are also being used in treating metastatic disease. Evolving knowledge regarding the different genetic abnormalities involved in the pathogenesis of PPGLs has identified potential therapeutic targets that may be utilized in the discovery of novel drugs.

Quality of life in multiple endocrine neoplasia type 2A compared with normative and disease populations

BACKGROUND

Patient-reported outcomes are measured in chronic disease states to inform intervention and management decisions while minimizing negative outcomes. We hypothesized that health-related quality of life in patients with multiple endocrine neoplasia type 2A would be worse than the general US population but similar to other chronic diseases.

METHODS

Adults ≥18 years with multiple endocrine neoplasia type 2A were recruited to complete the Patient-Reported Outcomes Measurement Information System 29-item questionnaire (n = 45). Scores based on the Patient-Reported Outcomes Measurement Information System T-score metric were compared with the general US population and with cohorts with low back pain, cancer, congestive heart failure, chronic obstructive pulmonary disease, major depressive disorder, rheumatoid arthritis, neuroendocrine tumors, primary hyperparathyroidism, and MEN1.

RESULTS

Compared with US normative data, multiple endocrine neoplasia type 2A patients reported worse anxiety (58.2 ± 12.0, P < .0001), depression (55.4 ± 12.0, P < .01), fatigue (61.4 ± 10.8, P < .0001), pain interference (54.0 ± 11.5, P < .05), and sleep disturbance (56.9 ± 2.7, P < .001), as well as significantly lower physical functioning (45.7 ± 9.3, P < .01) and ability to participate in social roles (46.4 ± 9.7, P < .05). Multiple endocrine neoplasia type 2A patients reported greater fatigue than patients with cancer (P < .0001), chronic obstructive pulmonary disease (P = .01), rheumatoid arthritis (P = .0002), neuroendocrine tumors (P = .0007), and primary hyperparathyroidism (P < .0001) but higher physical functioning compared with patients with rheumatoid arthritis (P = .02), low back pain, congestive heart failure, and chronic obstructive pulmonary disease (P < .0001).

CONCLUSIONS

This study is the first to use the Patient-Reported Outcomes Measurement Information System to compare patient-reported outcomes between multiple endocrine neoplasia type 2A and other chronic conditions. Individuals with multiple endocrine neoplasia type 2A reported worse health-related quality of life in all 7 domains compared with US normative data. Multiple endocrine neoplasia type 2A patients reported greater fatigue but greater physical function compared with several other conditions. Prospective longitudinal evaluation of patient-reported outcomes in multiple endocrine neoplasia type 2A should be conducted to identify treatments associated with the highest health-related quality of life.

The development of rapid and accurate screening test for RET hotspot somatic and germline mutations in MEN2 syndromes

Medullary thyroid carcinoma (MTC) is a rare endocrine malignancy with distinctive features separating it from other thyroid cancers. Cancer may be sporadic or occur as a consequence of the hereditary syndrome called multiple endocrine neoplasia type 2 (MEN2) with three distinct phenotypes in MEN2A, MEN2B and FMTC. Each variant of MEN2 results from different RET gene mutations, with a good genotype-phenotype correlation. The goal of the study was to develop a fast and accurate screening method for a reliable detection of hot-spot RET germline and sporadic tumor mutations. From a cohort of 191 patients with MTC and their relatives, 38 tested positive and 31 tested negative for a germline or somatic tumor RET mutation were selected. A positive HRM mutation pattern was detected in all mutation-positive patients and altogether the method was able to clearly differentiate between twenty different genotypes. A novel germline variant p.Ala639Thr was detected in MTC patient, which was determined to be likely benign. Analytical specificity was determined to be 98.6% and a sensitivity threshold was determined to be 30%. The fast and accurate HRM method reduces the turnaround time providing fast and important information, especially when targeted anti-tyrosine kinase therapy on tumor samples is considered. Overall, we developed a high-throughput, accurate and cost-effective approach for the detection of RET germline and sporadic tumor mutations.

An update on the genetics of pheochromocytoma

Pheochromocytomas (PHEOs) and paragangliomas (PGLs) are rare neuroendocrine tumors. About 30% or more of them are thought to be of inherited origin due to germ-line mutations in at least 10 well-characterized genes. There are data linking specific genotypes of these tumors to specific locations, typical biochemical phenotypes or future clinical behaviors. Conversely, clinical features, catecholamine production and immunohistochemistry evaluation can help with the proper order of genetic testing for PHEO and PGL. The identification of a germ-line mutation can lead to an early diagnosis, appropriate treatment, regular surveillance and better prognosis not only for the patient but also for their family members. Moreover, the latest discoveries in molecular pathogenesis of these tumors will provide an important basis for future personalized therapy.

Multiple endocrine neoplasia type 2A

Multiple endocrine neoplasia type 2A (MEN 2A) is an autosomal dominant inherited cancer syndrome that expresses nonendocrine and endocrine tumors. Here, we describe a 42-year-old man with an initial presentation of low back pain and hypertension. Clinical assessments revealed pheochromocytoma, medullary thyroid carcinoma with bone metastasis, and parathyroid hyperplasia. MEN 2A was diagnosed, and a family history of pheochromocytoma was traced. Surgical resection of the pheochromocytoma of the adrenal gland resulted in a cure of the patient's hypertension. He received systemic chemotherapy with the "MAID" regimen (mesna, doxorubicin, ifosfamide, and dacarbazine) over three cycles of 3 weeks each, and showed a partial response.

Primary hyperparathyroidism as the first clinical manifestation of multiple endocrine neoplasia type 2A in a 5-year-old child

BACKGROUND

Primary hyperparathyroidism occurs in only 10%-30% of patients with multiple endocrine neoplasia type 2A (MEN2A), rarely as the sole clinical manifestation, and is usually diagnosed after the third decade of life.

SUMMARY

A 5-year-old girl was referred for prophylactic thyroidectomy as she carried the p.C634R RET mutation. She was clinically asymptomatic, with a normally palpable thyroid and with the cervical region free of lymphadenopathy or other nodules. Preoperative tests revealed hypercalcemia associated with elevation of parathyroid hormone (PTH) (calcium = 11.2 mg/dL, calcium ion = 1.48 mmol/L, phosphorus = 4.0 mg/dL, alkaline phosphatase = 625 U/L, parathyroid hormone (PTH) PTH = 998 pg/mL). A thyroid ultrasound was normal and parathyroid scintigraphy with (99m)Tc-Sestamibi revealed an area of radioconcentration in the upper half of the left thyroid lobe suggesting hyperfunctioning parathyroid tissue. She underwent total thyroidectomy and parathyroidectomy and developed hypocalcemia. The anatomopathological examination showed no histopathological changes in the thyroid tissue and an adenoma of the parathyroid gland, confirming the diagnosis of hyperparathyroidism.

CONCLUSIONS

Primary hyperparathyroidism can be a precocious manifestation of MEN2A. This case report highlights that asymptomatic hypercalcemia should be scrutinized in children related to patients with MEN2A who carry a mutation in the RET proto-oncogene, especially mutations in the codon 634, before the currently recommended age of 8 years.