Endocrine Abstracts

JOINT3568

Introduction: Multiple endocrine neoplasia type 1 (MEN1) is a rare autosomal dominant disorder characterized by tumors of the parathyroid glands (PTG), pancreas, and anterior pituitary. Surgical management is often required, but long-term complications can be severe. Here, we present a unique case of a young patient with MEN1 and recurrent primary hyperparathyroidism (PHPT), who underwent total pancreatectomy, leading to diabetes mellitus (DM).

Clinical Case: A 27-year-old woman was diagnosed with MEN1 syndrome (heterozygous *c.203delC p.T70fsX118* mutation) following the incidental discovery of a pancreatic mass during an abdominal ultrasound. In 2012, she underwent resection of the right adrenal gland and cholecystectomy, along with total duodenopancreatectomy for multiple pancreatic tumors, which were histologically confirmed as somatostatinomas. As a result, she developed fulminant diabetes, necessitating intensive insulin therapy. In 2013, at the Endocrinology Research Centre, she underwent paraadenomectomy of four hyperplastic PTGs with autotransplantation of parathyroid fragments into the right forearm due to symptomatic PHPT. However, despite surgery, PTH levels remained persistently high. A modified Casanova confirmed high PTH production recurrence at the site of autotransplantat but with “hypoparathyroid” dependance on 2 mg of alfacalcidiol and 1000 mg of calcium consistent with immunoactive but inactive PTH circulation. After three years of calcium and alfacalcidol therapy, PTH levels was 84 pg/ml (non autotransplanted arm), with corrected calcium at 2.58 mmol/l(2.15–2.55) and normocalciuria. Given the continued elevation of PTH and calcium, further diagnostic workup was undertaken. Ultrasound revealed hyperplasia of the autotransplanted PTG fragments in the right forearm muscle. A repeat Casanova test confirmed recurrent PHPT, prompting autograft removal, which resulted in PTH decrease (8.3 pg/ml) and reintroduction of “hypoparathyroid” state. Additionally, brain MRI identified a 2.3 × 4.4 mm pituitary adenoma. Two years later, the patient was diagnosed with hyperprolactinemia, with stable adenoma size, and was prescribed cabergoline. In 2020, due to worsening glycemic control (HbA1c 7.5%), she was transitioned to insulin pump therapy, leading to stabilization within individual target ranges. Screening for diabetic complications revealed diabetic distal polyneuropathy. Currently, the patient exhibits positive clinical outcomes, including PHPT remission and optimized glycemic control.

Results: This case highlights the complexities of identifying the primary source of PTH secretion in patients with autotransplanted PTG fragments, the risks associated with repeated surgeries, and the challenges of achieving glycemic stability in absolute insulin deficiency.