Endocrine Abstracts

Background: Management of primary hyperparathyroidism (PHPT) in Multiple Endocrine Neoplasia type 1 syndrome (MEN 1) is still a challenge. PHPT developing in MEN 1 is characterized by the involvement of all parathyroid glands. Therefore, by modern guidelines, total or subtotal removal of the parathyroid glands is recommended. But this approach often leads to the development of hypoparathyroidism, adequate correction of which is not always possible. Drug therapy of recurrent PHPT in MEN 1 patients may be the alternative to radical surgery. We present a clinical case of MEN 1 patient in whom somatostatin analogue therapy resulted in normalization of serum calcium level.

Clinical case: 40 years old Caucasian woman, with a history of insulinoma, that was operated on at the age of 10 and prolactin-secreting pituitary macroadenoma diagnosed at the age 19. In 2015 the patient was tested for PHPT, iPTH level was 28 pmol/l (1.3-9.3), serum Ca⁺⁺ level - 1.47 mmol/l (1.13 – 1.29), CT scans revealed two lesions suspicious for parathyroid adenomas. Subtotal parathyroidectomy of both right and left lower parathyroids glands was performed. Postoperative iPTH was 5.2 pmol/l. All removed lesions were confirmed to be parathyroid adenomas by the pathology examination. Genetic testing was done and variant in MEN1 gene was found. In 2020 PHPT recurrence was confirmed (iPTH 200.10 pg/ml (15.0 – 68.3)), serum Ca⁺⁺ level 1.57 mmol/l (1.11 – 1.29), serum total Са 2.78 mmol/l (2.15 – 2.65)). 68Ga-DOTA-TATE PET/CT was carried out, it revealed three lesions in the pancreas head and body which intensively accumulated radiopharmaceutical, also 68Ga-DOTA-TATE positive foci was found in the projection of the left upper parathyroid. Subsequently endosonography was performed; it showed multiple lesions in pancreas and submucosal lesions in duodenum. Fine needle aspiration biopsy of pancreatic and duodenal formations confirmed neuroendocrine tumors in all of them. Preoperative short-acting somatostatin analogue (Octreotide) was started. Subtotal pancreatectomy, 2/3 stomach resection, duodenectomy were performed. After surgery octreotide therapy was continued. After 6 weeks of octreotide therapy сalcium and parathyroid hormone levels were assessed. Decrease of iPTH and calcium levels was found: iPTH from 172,5 to 122 pg/ml (15.0 – 68.3), serum total Ca from 2,73 to 2.59 mmol/l (2.15 – 2.65).

Conclusion: Our clinical case demonstrated the ability of octreotide to reduce iPTH and normalize calcium levels in a patient with MEN 1 syndrome. It is necessary to further study the potential of somatostatin analogues in the treatment of recurrent PHPT in MEN 1 syndrome.