Endocrine Abstracts

Introduction: Parathyroid adenomas are the main cause of primary hyperparathyroidism. They are usually small – weighing <1 g – and not easy to find – requiring meticulous imaging studies for localisation. Giant adenomas are uncommon; large tumours and high levels of PTH raise the suspicion of parathyroid malignancy.

Case presentation: A 68-year-old female presented in our clinic with polydipsia, poliuria, nausea, weight loss, and extreme muscular weakness – she wasn’t able to walk – and depressive mood. Clinical exam revaled dehydration and right cervical mass. Calcium was 21 mg/dl and PTH was 2238 pg/ml. The patient was also vitamin D deficient – 25OH vitamin D 14 μg/l. Radiographic study showed fracture of the first lumbar vertebra, CT scan showed multiple osteolytic areas of the skull. Osteodensitometry demonstrated osteoporosis (lumbar spine T score −2.9 S.D. and distal radius T score −6.7 S.D.). Ultrasonography revealed a hypoechoic inhomogeneous mass, 38/30/45 mm, laterally and caudally to the right thyroid lobe. Parathyroid scintigraphy (99Tc-MIBI) demonstrated a large area of high uptake in that region. The patient received intravenous fluids, loop diuretic, i.v. bisphosphonate (zoledronate) and calcitonin to reduce the level of calcium, then she was successfully operated. Calcemia dropped after surgery and it was managed with i.v. calcium and alpha calcidol. Mild hypocalcemia persisted for more than 6 months thereafter and so did the high levels of PTH, that raised to 506.5 pg/ml, then returned to normal – the hungry bones syndrome. The pathologic diagnosis was benign parathyroid tumour – parathyroid adenoma.

Conclusions: This is a rare case of giant parathyroid adenoma. The peculiarities of the case are the size of the tumour, the very high level of calcium and PTH – suggesting a malignant tumour, and the persistence of high levels of PTH and hypocalcemia months after surgery.