Supplementary Material for: Primary hyperparathyroidism: a rare form of presentation

Introduction: Primary hyperparathyroidism (PHPT) typically presents as asymptomatic hypercalcemia or, less frequently, with complications such as bone disease and/or nephrolithiasis. Acute pancreatitis (AP) as the initial manifestation of PHPT is rare.

Case Presentation: A 37-year-old man was admitted due to AP. The initial tests revealed elevated amylase and lipase levels, hypercalcemia (14.9mg/dL), and hypophosphatemia. Further investigation showed elevated serum PTH (1241pg/mL), suggesting PHPT. 99mTc-Sestamibi scintigraphy and neck CT scan identified a right inferior parathyroid nodule, therefore the patient underwent right inferior parathyroidectomy. Histology revealed a parathyroid adenoma. Postoperative tests showed normal PTH, calcium, and phosphorus levels. There has been no recurrence of pancreatitis.

Conclusions: This case shows that, although uncommon, PHPT can present as AP. It is also noteworthy that although histology suggested parathyroid adenoma, this patient presented with severe hypercalcemia and very high serum PTH, which are predictive factors of parathyroid carcinoma. Therefore, close monitoring will be required.