Endocrine Abstracts

66-year old woman came first for an evaluation of nodular thyroid disease. Primary hyperparathyroidism (PHPT) was incidentally diagnosed during the entrance lab test with total calcium 2.62 mmol/l and PTH 93 ng/l. Serum creatinine was normal and 25 OH vitamin D was 97 nmol/l. Dual-energy X-ray absorptiometry was carried out and revealed osteoporosis at lumbar spine. Moreover, there were two low-trauma fractures in a recent patient history. Although hypercalcemia was mild, the presence of osteoporosis constituted an indication for surgical treatment of PHPT. Neck ultrasound found a hypoechogenic lesion of 0.2 ml behind the cranial third of the left thyroid lobe evocative of a left superior hyperfunctioning parathyroid gland. 99mTc-MIBI double-phase scintigraphy was, however, negative. Due to inconclusive conventional imaging 18F-fluorocholine PET-CT was recommended and localized four abnormal parathyroid foci suggestive of parathyroid hyperplasia and/or multigland parathyroid disease. Basic assessment of hereditary forms of PHPT was, therefore, carried out. Prolactin, IGF1, chromogranin A and calcitonin were normal; calcium/creatinine excretion ratio was 2,2%. No relatives affected with hypercalcemia were found. In a postmenopausal woman with normal renal functions and sufficient vitamin D level a sporadic form of PHPT with a single adenoma would be the most expected. The result of 18F-fluorocholine PET-CT was probably modified by thyroid nodules present in both thyroid lobes. The definitive diagnosis will be made by a surgeon during bilateral cervical exploration. The present case shows how a combination of both false negative and false positive preoperative imaging might influence the extent of preoperative evaluation and the choice of surgical approach in PHPT.