Endocrine Abstracts

Case History: 29 year old lady presented with profuse diarrhoea, lethargy and hypokalaemia in 2010. CT scan confirmed mass lesion in tail of pancreas. Chromogranin A and 24 hour urinary 5HIAA were normal. Fasting Gut hormone level showed elevated level of Vasoactive Intestinal Peptide (VIP), suggesting diagnosis of VIPoma. Further investigations confirmed hyperparathyroidism and microprolactinoma.

Investigations: Adjusted calcium 2.98 mmol/l (<2.55), phosphate 0.25 mmol/l (0.81–1.45), Parathyroid hormone 17.6 pmol/l (<6.9), 24 hour urinary calcium 14.6 mmol/24 hours (<7.5), prolactin 2287 mu/l (<496). MRI pituitary with contrast confirmed pituitary microadenoma. Ultrasound parathyroid and Sestamibi scan confirmed left superior parathyroid adenoma.

Results and treatment: Patient underwent distal pancreatectomy and splenectomy in 2011 and histology revealed pancreatic endocrine neoplasm, with Ki67 stain <2% cells and cells stained positive for VIP. Genetic testing showed MEN-1 mutation. Later in 2011, she went onto have parathyroidectomy and intraoperative frozen section confirmed left superior parathyroid adenoma and solitary parathyroidectomy was performed. Her calcium and PTH levels normalised and patient improved symptomatically. Cabergoline was initiated for microprolactinoma. She was followed up annually and remained well. In 2020, she noticed symptoms of lethargy and investigations showed elevated calcium at 2.69 mmol/l, elevated PTH of 12.2 pmol/l and elevated 24 hour urinary calcium of 9.5 mmol/24 hours, confirming recurrence of hyperparathyroidism. Further imaging in 2020 with ultrasound scan showed two parathyroid adenomas measuring 0.9 cm and 1.18 1 cm in right mid pole and right lower pole and confirmed on Sestamibi scan. She has been referred to tertiary centre for subtotal (3.5 gland) parathyroidectomy.

Conclusion: Recurrent hyperparathyroidism in patients with multiple endocrine neoplasia type 1 is frequent if fewer than 3 glands are removed at initial parathyroidectomy. Since all glands in patients with MEN1 have the menin mutation, any parathyroid tissue left is at risk of developing into hyperfunctioning gland. To achieve lowest possible rate of recurrence, surgeons advocate subtotal (3.5 glands) or total parathyroidectomy with forearm auto transplantation. However this risks permanent hypoparathyroidism, which can greatly affect quality of life. Several reports also show some patients do not develop recurrence despite solitary adenoma removal, especially with ability to preoperatively localize lesions and some surgeons have begun less aggressive initial parathyroidectomy.