Endocrine Abstracts

Background: Parathyroid carcinoma (PC) is a rare cause of primary hyperparathyroidism (PHPT) and extremely rare endocrine malignancy during pregnancy. Different maternal and fetal/neonatal complications of PHPT occur in 67 and 80% of untreated cases respectively, probably more due to severe hypercalcemia.The diagnostic and therapeutic approaches are limited in pregnant women and require individual risk-benefit assessment.

Aim: We present a case of PC manifested during pregnancy when delayed treatment led to severe complications.

Clinical case: Young woman suffered from urolithiasis since the age of 19. Moreover, she had a history of multiple low-energy bone fractures of limbs. At the age of 35 lab tests showed high PTH (55,51 pmol/l (NR 1,6–6,9)) and hypercalcemia (total calcium 3,28 mmol/l), US detected a tumor of the left inferior parathyroid gland 33x25x18 mm (PG). So, PHPT was diagnosed at 29 week of gestation. Given severe hypercalcemia and gestational age parathyroidectomy was recommended but the patient refused the surgery as well as cinacalcet therapy. Cesarean section was performed at 38 week of pregnancy without any complications. The woman breastfed for 1,5 years. During this period, the patient had low-energy fractures of left humerus that required osteosynthesis. 2 years after delivery exam showed albumin-adjusted calcium 2.9 mmol/l, PTH 1044 pg/ml (15–65), 24-hours urinary calcium 13.3 mmol. US, CT scan, 99mTc-sestamibi scintigraphy confirmed tumor of the left inferior PG. The patient had bilateral nephrolithiasis, significant BMD reduction (Z-score radius −5.9 S.D.), also osteitis fibrosa cystica and vertebrae fractures (Th8-9,12) were verified. The parathyroidectomy was carried out, PTH and total calcium decreased to 50.1 pg/ml and 2.18 mmol/l respectively on the fifth day after surgery, oral calcium supplementation and alfacalcidol were prescribed. Morphological examination revealed PC, pT1NxM0.

Conclusion: Parathyroidectomy is a preferable treatment for patients with symptomatic PHPT in the second trimester of pregnancy. Severe hypercalcemia accompanied with high PTH and large tumor size are suspicious for PC. Mutation of CDC73 should be examined to assess the prognosis in patients with confirmed PC.