Genotype-Phenotype Correlation in Indian Patients with MEN2-Associated Pheochromocytoma and Comparison of Clinico-Pathological Attributes with Apparently Sporadic Adrenal Pheochromocytoma

[Metastatic pheochromocytoma in multiple endocrine neoplasia type 2A]

Pheochromocytoma (PHEO) currently is considered to be malignant due to metastatic potential. One of the most common familial forms of PHEO is multiple endocrine neoplasia syndrome (MEN) type 2. The penetrance of PHEO in MEN2 syndrome is up to 50% of cases. It may be one- or two-sided, but metastases occur extremely rare. The fact that in majority of cases of MEN2 syndrome the source of distant metastases is medullary thyroid carcinoma (MTC) complicates differential diagnosis in case of PHEO metastasis.Isolated cases of PHEO with metastases to the lymph nodes, lungs, liver, bones, brain in MEN2 patients were described. In the available literature, we have found a description of 31 cases of metastatic PHEO in MEN2 syndrome. The available data of those cases is presented as a table in the article.We present a description of a 40-year-old woman with MEN2A syndrome (mutation of the RET proto-oncogene p.Cys634Tyr), with a history of twice-performed surgical treatment of MTC, with daily crises of arterial hypertension accompanied by vegetative symptoms, with a giant bilateral PHEO (up to 200 m on the right and up to 150 mm on the left) with synchronous large metastasis (up to 50 mm) into the pubic bone with the destruction. The patient underwent several surgeries: bilateral adrenalectomy, then a bilateral revision of the neck, removal of the right upper and right lower parathyroid glands, residual thyroid tissue, then resection of the right pubic bone with a tumor.

Total versus partial adrenalectomy in bilateral pheochromocytoma - a systematic review and meta-analysis

BACKGROUND

In patients with bilateral pheochromocytoma, partial adrenalectomy offers the chance to preserve adrenal function and avoid the need for lifelong steroid supplementation. However, the risk of tumour recurrence raises questions about this procedure. The aim of our study was to compare partial and total adrenalectomy in bilateral pheochromocytoma through a systematic review with meta-analysis.

METHODS

A systematic search was carried out using databases (MEDLINE, EMBASE, Scopus, Web of Science, CENTRAL) and registers of clinical trials (ClinicalTrials.gov, European Trials Register, WHO International Trials Registry Platform). This meta-analysis included studies up to July 2022 without language restrictions. A random effects model meta-analysis was performed to assess the risk of tumor recurrence, steroid dependence and morbidity in these patients.

RESULTS

Twenty-five studies were included in the analysis involving 1444 patients. The relative risk (RR) of loss of adrenal hormone function during follow-up and the need for steroid therapy was 0.32 in patients after partial adrenalectomy: RR 0.32, 95% Confidence Interval (CI): 0.26-0.38, P < 0.00001, I2 = 21%. Patients undergoing partial adrenalectomy had a lower odds ratio (OR) for developing acute adrenal crisis: OR 0.3, 95% CI: 0.1-0.91, P=0.03, I2 = 0%. Partial adrenalectomy was associated with a higher risk of recurrence than total adrenalectomy: OR 3.72, 95% CI: 1.54-8.96, P=0.003, I2 = 28%.

CONCLUSION

Partial adrenalectomy for bilateral pheochromocytoma is a treatment that offers a chance of preserving adrenal hormonal function, but is associated with a higher risk of local tumor recurrence. There was no difference for the risk of metastasis and in overall mortality among the group with bilateral pheochromocytomas undergoing total or partial adrenalectomy. This study is in line with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) and AMSTAR (A Measurement Tool to Assess Systematic Reviews) Guidelines (10, 11).

SYSTEMATIC REVIEW REGISTRATION

https://osf.io/zx3se.

Hereditary Medullary Thyroid Carcinoma: Genotype, Phenotype and Outcomes in a North Indian Cohort

BACKGROUND

Aggressiveness of hereditary medullary thyroid carcinoma (hMTC) has been conventionally described to correlate with American Thyroid Association (ATA) risk groups based on RET mutations. Recent evidence increasingly contradicts this notion. We studied the RET genotype and its correlation with disease phenotype and survival outcomes in a cohort of hMTC patients.

METHODS

In a retrospective cohort of 55 hMTC patients from 23 families treated at a north Indian tertiary care institute over 15-years, RET genotype was correlated with disease phenotype (clinical, biochemical, and pathological attributes) and outcomes in terms of biochemical cure (normalization of serum calcitonin), structural cure, overall survival (OS) and disease specific survival (DSS).

RESULTS

Forty-nine patients had Multiple Endocrine Neoplasia (MEN)-type 2A syndrome, 02 had MEN-2B, and 4 had familial MTC. Two patients belonged to highest ATA risk, 41 to high-risk, and 12 to moderate risk categories. Age of the patients or stage of disease at presentation did not differ significantly between the ATA risk groups. Though the baseline serum calcitonin was significantly higher in highest risk category, the biochemical cure rates were not significantly different. At a median follow up of 48 months (Inter-quartile range 18-84, range 12-192) structural cure rates in ATA moderate and high risk groups were significantly higher than highest risk group (p = 0.04). No significant difference in OS between the three ATA groups of hMTC among the patients who underwent surgical treatment was observed (p = 0.098).

CONCLUSIONS

The ATA moderate and high risk groups have better structural cure rates compared to ATA highest risk group. The biochemical cure and overall survival rates did not significantly differ between ATA risk-groups, and were impacted by the disease stage at presentation. The current ATA risk-groups do not reliably predict the outcomes in terms of biochemical cure and survival in hMTC patients.

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.

Long-term Clinicopathological Features of a Family with Multiple Endocrine Neoplasia Type 2A Caused by C634R RET Gene Mutation

Type 2 multiple endocrine neoplasia (MEN2A) is a variant of hereditary medullary thyroid carcinoma (MTC). MEN2A is characterized by the presence of the following: MTC, hyperparathyroidism, and pheochromocytoma (PHEO). The pathogenesis includes RET proto-oncogene mutation; the most frequently observed mutation is in exon 11 codon 634. We report pedigree of a large Indian family involving three generations including 21 members with MEN2A, in whom RET mutation status was determined. We then analyzed their clinical follow-up details, with a median duration of follow-up of 60 months (range: 9-276 months). Calcitonin (Ctn) levels were routinely checked during the follow-up. The index case was found to carry p.C634R mutation involving exon 11 of the RET gene. RET mutation was positive in 12 members in the family (12/21, i.e., 57%), was negative in 7 patients, and was not tested in 2 patients, as they were not available for the genetic test. Thirteen were clinically affected with MTC and 10 members had PHEO. At the last follow-up, the median Ctn level was 14.3 pg/mL (range: 2-12655 pg/mL). Four patients developed lymph nodal recurrence during follow-up, for which they underwent re-operations with median duration to recurrence being 48 months (range: 9-156 months). We highlight in this article that early diagnosis, adequate surgery, and appropriate genetic counseling with genetic screening are essential to improve the outcome of persons with MTC. Every case of MTC should be seen as familial or index case of hereditary MTC unless otherwise RET mutation excludes it.

Genetic Profile of Indian Pheochromocytoma and Paraganglioma Patients - A Single Institutional Study

BACKGROUND AND AIMS

Pheochromocytomas (PCCs) and Paragangliomas (PGL) are rare catecholamine producing tumors that may present in sporadic or familial settings. Despite vast strides in understanding of PCC/PGL genetics in the last two decades, there is a dearth of information from India. The aim here is to study the prevalence of genetic mutations in Indian PCC/PGL patients.

SETTINGS AND DESIGN

Tertiary care academic hospital; prospective study.

METHODS

50 histopathologically diagnosed PCC/PGL patients formed the study group. Clinical, biochemical, pathological attributes and outcomes were documented and the phenotype was compared to the genotype. Succinyl dehydrogenase (SDH), Re-Arranged during Transfection (RET), Von-Hippel-Lindau (VHL) and NeuroFibromatosis-1 (NF1) mutations were studied. Additionally, immunohistochemisty for SDHB was also done, and the results compared to mutational analysis of SDH by MLPA (Multiplex Ligation-dependent Probe Activation).

STATISTICAL ANALYSIS

Independent samples t-test and Fisher's exact test were used as appropriate. P values ≤0.05 were considered statistically significant.

RESULTS

The mean age was 34.3 years. Of the 50 patients, 27 were males and 23 females. 10 patients (20%) in all were detected to have a genetic mutation. 6 patients possessed a RET mutation, while two had VHL mutations. No patient presented with a NF1 mutation. 2 patients had a SDH mutation, and Immunohistochemistry for SDHB correlated with mutational analysis for these patients.

CONCLUSIONS

The proportion of patients with a familial variant of PCC/PGL is more than what the historic "Rule of Ten" suggests. Our study found that one in five patients have a genetic mutation. PCC/PGL patients with genetic mutations not only require more stringent follow-up, but also screening of family members.

Endocrine neoplasms in familial syndromes of hyperparathyroidism

Familial syndromes of hyperparathyroidism, including multiple endocrine neoplasia type 1 (MEN1), multiple endocrine neoplasia type 2A (MEN2A), and the hyperparathyroidism-jaw tumor (HPT-JT), comprise 2-5% of primary hyperparathyroidism cases. Familial syndromes of hyperparathyroidism are also associated with a range of endocrine and nonendocrine tumors, including potential malignancies. Complications of the associated neoplasms are the major causes of morbidities and mortalities in these familial syndromes, e.g., parathyroid carcinoma in HPT-JT syndrome; thymic, bronchial, and enteropancreatic neuroendocrine tumors in MEN1; and medullary thyroid cancer and pheochromocytoma in MEN2A. Because of the different underlying mechanisms of neoplasia, these familial tumors may have different characteristics compared with their sporadic counterparts. Large-scale clinical trials are frequently lacking due to the rarity of these diseases. With technological advances and the development of new medications, the natural history, diagnosis, and management of these syndromes are also evolving. In this article, we summarize the recent knowledge on endocrine neoplasms in three familial hyperparathyroidism syndromes, with an emphasis on disease characteristics, molecular pathogenesis, recent developments in biochemical and radiological evaluation, and expert opinions on surgical and medical therapies. Because these familial hyperparathyroidism syndromes are associated with a wide variety of tumors in different organs, this review is focused on those endocrine neoplasms with malignant potential.