Endocrine Abstracts

Multiple endocrine neoplasia (MEN) 1 is a rare hereditary autosomal dominant tumor syndrome characterized by two or more endocrine tumors. Non-endocrine neoplasms have been described as well. MEN1 is caused by inactivating mutations of the onco-suppressor gene MEN-1 (chromosome 11q13) which encodes the protein menin. Currently, 897 public variants of MEN-1 gene are reported. We present the case of a recently discovered pathogenic mutations of MEN-1 gene. A 32-year-old Italian male patient, admitted to our outpatient for osteopenia and nephrolithiasis in hypercalcemia and hypophosphatemia. Primary Hyperparathyroidism, confirmed both biochemically and morphologically (neck ultrasound plus ¹¹C-methionine PET-CT), was sustained by left superior parathyroid gland. The patient, after ruling-out pheochromocytoma diagnosis, underwent subtotal parathyroidectomy (left superior and inferior, right superior) since three hyperplastic parathyroid were found during the surgery. Pituitary hormones were evaluated, with no sign of pituitary hyper/hyposecretion, except for a single finding of high ACTH level. Pituitary MRI showed an 8 mm lesion suggestive for microadenoma. Cushing syndrome biochemical assessment was equivocal. The concomitant detection of high level of chromogranin A prompted us to perform an abdominal MRI, in the suspicion of neuroendocrine tumor (NET). The MRI showed three pancreatic lesions (12 mm in the pancreatic head, 8 and 3 mm in the pancreatic tail); moreover, it showed a 4 cm lesion of the medial lip of the left adrenal gland. ⁶⁸Ga PET-CT was performed, showing high radionuclide uptake, suggestive of high expression of somatostatin receptors, in the pancreatic area and left adrenal gland. Ultrasound endoscopy and subsequent biopsy of the pancreatic lesions confirmed the diagnosis of pancreatic NET G1. As regard the left adrenal nodule, no signs and symptoms of adrenal hormones hypersecretion were detected. The ¹³¹I-Norcholesterol scintigraphy revealed a unilateral left adrenal gland uptake. The patient underwent left adrenal surgery due to the dimension of the nodule. Histology confirmed left adrenal adenoma. Genetic testing (MEN-1 gene exon 2-10 DNA-sequencing) identified a missense MEN1 heterozygous pathogenic variant MEN1(NM_130799.2):c.758delC (p.Ser253CysfsTer28) rs1592648765 in exon 4. The patient is now under somatostatin analogues and monitored by MRI and hormonal follow-up. Genetic inheritance is under investigation. We have described for the first time the clinical consequence of a recently discovered pathogenic mutation associated with four different endocrine neoplasms. MEN1 represents a complex syndrome, as it has plenty of possible clinical manifestations and a deep and still surprising panel of mutations and genetic variants. A potential genotype-phenotype correlation is still far to be recognized.