Endocrine Abstracts

JOINT2948

Introduction: Multiple endocrine neoplasia type 1 (MEN1) is a rare hereditary endocrinopathy with a prevalence of 1–9 cases per 100,000. It is characterized by the development of multiple endocrine and non-endocrine tumors, with the classical triad involving the parathyroid glands, pituitary gland, and duodenopancreatic neuroendocrine tumors (NETs).

Clinical Case Description: Since the age of 27, Patient M. experienced episodes of tremor and visual disturbances associated with fasting. At 37 years old, following recurrent renal colic episodes, kidney ultrasound revealed a left adrenal tumor. Further evaluation showed elevated prolactin levels (4,200 IU/ml; reference range: 63.6–349.8), and brain MRI confirmed the presence of a pituitary adenoma. One year later, the patient was started on cabergoline 0.5 mg twice weekly. Concurrently, laboratory tests showed increased parathyroid hormone (PTH) levels (26.2 pmol/l; reference range: 1.16–7.06), hypercalcemia (ionized calcium: 1.51 mmol/l; reference range: 1.10–1.30), and vitamin D deficiency (13.85 ng/ml). Thyroid and parathyroid ultrasound revealed a thyroid nodule in the right lobe and a smaller hypoechoic lesion. Chest CT identified multiple rounded foci in both lungs. At age 39, prolactin levels remained elevated despite increasing the cabergoline dose to 1.5 mg weekly. MRI confirmed persistent pituitary adenoma, and the patient was diagnosed with primary hyperparathyroidism. Additionally, thyroid ultrasound revealed a 36×24×20 mm nodule in the right lobe, classified as EU-TIRADS 4. Fine-needle aspiration biopsy indicated a Bethesda IV lesion, while calcitonin levels were 6.6 pg/ml. Further investigations revealed multiple pancreatic NETs on abdominal CT and nodular adrenal hyperplasia in both glands. A 72-hour fasting test confirmed fasting hypoglycemia with elevated proinsulin levels. Chest CT showed multiple pulmonary foci (3–11 mm). Physical examination revealed numerous papillary skin formations on the torso, forearms, legs and feet, histologically established to be fibromas. The patient underwent thyroidectomy and parathyroidectomy, with histological analysis confirming follicular thyroid carcinoma in the right lobe and parathyroid hyperplasia. After completing radioactive iodine therapy, whole-genome sequencing identified a de novo MEN1 mutation. Three months later, the patient underwent partial resection of the right lower lung lobe. Immunohistochemical analysis confirmed a Grade 2 atypical pulmonary carcinoid. Consequently, combination therapy with capecitabine and temozolomide was initiated.

Conclusion: This case underscores the importance of comprehensive diagnostic evaluation in patients with MEN1. While the classical triad of tumors is well recognized, MEN1 patients may present with a broader spectrum of neoplasms, necessitating individualized and multidisciplinary treatment approaches.