Multiple endocrine neoplasia type 1 (MEN-1; OMIM 131100) is a rare, autosomal dominant syndrome caused by heterozygous inactivating mutations in the MEN1 tumor suppressor gene (11q13; OMIM 613733). MEN-1 is characterized by polyglandular pathology, which typically involves the parathyroid glands (90%), pancreas (30-80%) and anterior pituitary (15-50%). To date, over 1,600 pathogenic MEN1 variants have been documented, including nonsense, frameshift, and splice-site mutations, as well as rare large deletions. While germline mutation detection rates reach 70-90% in clinically diagnosed probands, approximately 10-30% of phenotypically confirmed MEN-1 families test negative by conventional sequencing, suggesting possible regulatory region defects, deep intronic mutations, or mosaic variants. In cases where MEN1 germline testing is negative despite a clinical MEN-1 phenotype, somatic mosaicism should be considered. We investigated a familial cohort presenting with primary hyperparathyroidism, multifocal pancreatic and pituitary neuroendocrine neoplasms - a triad strongly suggestive of MEN-1. Using a multi-tissue sequencing approach, we analyzed DNA extracted from peripheral blood leukocytes and parathyroid adenomas tissue via both Sanger sequencing and next-generation sequencing (NGS) with high coverage. While conventional Sanger analysis failed to detect a mutation, targeted NGS revealed a novel, likely pathogenic MEN1 variant present at low allele frequency (5-15%), consistent with postzygotic mosaicism. The variant was classified as pathogenic per ACMG/AMP guidelines and correlated with disease manifestations in affected tissues. These findings demonstrate that high-coverage NGS of multiple tissues is critical for identifying low-level mosaic MEN1 mutations missed by standard testing. Alternative screening methods are required for patients with strong clinical indications of MEN-1 and/or a family history, but negative germline test results, one such method is NGS with high coverage.

To evaluate the significance of increased of intraoperative parathyroid hormone(IOPTH) 10 min after parathyroidectomy in primary hyperparathyroidism. All patients underwent parathyroidectomy were retrospectively included. Following the results of IOPTH, three groups were defined: Group 1: increased of IOPTH, Group 2: <50 % decreased of IOPTH, and Group 3: >50 % decreased of IOPTH. Unilateral approach was performed and shifted to bilateral neck exploration(BNE) when indicated. There were single adenoma, double adenomas, and hyperplasia in 84 %, 5 %, and 11 % of cases respectively. We noted that 100 %, 80 %, and 4 % of patients had a polyglandular diseases in Groups 1, 2, and 3 respectively. Double adenoma and hyperplasia were present in 55 %, and 45 %, 22 %, and 58 %, 1 %, and 3 % in Groups 1, 2, and 3 respectively. Female patients represented 55 %, 71 %, and 81 % of patients in Groups 1, 2, and 3 respectively. Cure rate was 99 %. Patients with increased of IOPTH level 10 min after parathyroidectomy had a polyglandular diseases in 100 % of cases and needed BNE.

A man in his late 30s with gait difficulty, dysarthria, impaired consciousness and polyuria was diagnosed with left thalamic infarction. Hypercalcaemia (3.52 mmol/L (2.15-2.52)), high intact-parathyroid hormone (i-PTH) levels (88.8 pmol/L (1.1-6.9)) and high D-dimer levels (14.7 mg/L (<1.0)) were identified, followed by a positive microbubble test on transesophageal echocardiogram, suggesting high-risk patent foramen ovale (PFO) for ischaemic stroke. Paradoxical cerebral embolism via PFO, complicated by a hypercoagulable state and hypercalcemic dehydration, was considered. Polyglandular parathyroid hyperplasia, plus radiolucent mandibular tumours, suggested multiple endocrine neoplasia type 1 (MEN1) or hyperparathyroidism-jaw tumour syndrome. Genetic testing confirmed MEN1. Treatment was 24 mg of oral evocalcet and total parathyroidectomy with forearm autotransplantation, resulting in improved serum calcium and i-PTH levels. Finally, he underwent transcatheter PFO closure. We emphasise careful, etiological pursuit in young-onset stroke and the usefulness of genetic testing in differentiating hyperparathyroidism associated with mandibular tumours.

Autoimmune Addison's disease (AAD) is a rare condition occurring either in isolation or associated with other autoimmune diseases as part of an autoimmune polyglandular syndrome (APS) type 1, 2 or 4. Multiple endocrine neoplasia (MEN) type 1, 2 or 4 is a hereditary autosomal dominant cancer syndrome. Medullary thyroid carcinoma and pheochromocytoma are neoplasms common to MEN-2a and MEN-2b. We describe a unique, complex case of a man resulted affected by both APS-2 and MEN-2a. The patient developed Hashimoto's thyroiditis, diabetes mellitus type 1 and AAD, despite testing negative for adrenal cortex autoantibodies (ACA) and steroid 21-hydroxylase autoantibodies (21-OHAb). Moreover, he had also a family history for MEN-2a and he first developed medullay thyroid cancer, then bilateral pheochromocytoma on the adrenal substrate of an AAD. On adrenal histology we found complete bilateral cortical atrophy in the presence of a lymphocytic infiltration and fibrosis, confirming an ACA and 21-OHAb-negative AAD. This datum is the first documented in a living individual and confirms that the absence of autoantibodies is not incompatible with an autoimmune disease and confirms that AAD is a cell-mediated autoimmune disease limited to the adrenal cortex and sparing medullary. In the light of a literature review concerning the association between APS and MEN, this is the first proven case to be reported in humans. Finally, our findings suggest that adrenal medullary tumor can develop even on an adrenal gland with cortical atrophy due to autoimmune adrenalitis.

Immune checkpoint inhibitors are a promising class of anticancer drugs. The clinical benefits afforded by immune checkpoint inhibitors can be accompanied by immune-related adverse events that affect multiple organs, and endocrine immune-related adverse events include thyroiditis and hypophysitis. Hypophysitis is less frequent and has a less severe clinical presentation in patients treated with other immune checkpoint inhibitors, such as nivolumab, pembrolizumab, and atezolizumab, than in those treated with ipilimumab. However, studies have described isolated adrenocorticotropic hormone deficiency cases associated with nivolumab, pembrolizumab, and atezolizumab therapy, most of which occurred during the course of immune checkpoint inhibitor therapy. We report a rare case of patient with isolated adrenocorticotropic hormone deficiency that occurred after nivolumab therapy. A 69-year-old Japanese woman with advanced lung adenocarcinoma developed painless thyroiditis with transient elevations of serum thyroid hormones during 3 months of cancer treatment with nivolumab and began thyroid hormone replacement therapy for subsequent primary hypothyroidism. Four months after nivolumab therapy was discontinued, she developed isolated adrenocorticotropic hormone deficiency; corticosteroid replacement therapy relieved her secondary adrenal insufficiency symptoms, such as anorexia and fatigue. Human leukocyte antigen typing revealed the presence of DRB1*04:05-DQB1*04:01-DQA1*03:03 and DRB1*09:01-DQB1*03:03-DQA1*03:02 haplotypes, which increase susceptibility to autoimmune polyendocrine syndrome associated with thyroid and pituitary disorders in the Japanese population. Our patient developed thyroiditis during cancer treatment with nivolumab and subsequently exhibited isolated adrenocorticotropic hormone deficiency 4 months after discontinuing the drug. Administration of nivolumab in combination with a genetic predisposition to polyglandular autoimmunity probably caused both the thyroiditis and hypophysitis, resulting in primary hypothyroidism and isolated adrenocorticotropic hormone deficiency, respectively, in our patient. The present case highlights the need for physicians to be aware that endocrine immune-related adverse events, including hypophysitis, can occur more than several months after discontinuing a drug.