Endocrine Abstracts

Case History: A 61-year-old Caucasian female from Ukraine presented with severe hypercalcaemia following routine blood tests performed by the GP. She reported symptoms of back pain and joint pains. She had renal stones 10 years prior. No history of thiazide or lithium use. No red flags; no change in appetite or weight loss. There was no familial history of Multiple Endocrine Neoplasia (MEN). Examination of her neck, cardiorespiratory, abdomen and breasts were normal.

Investigations: Initial corrected calcium in hospital was 3.81mmol/l (2.2-2.62 mmol/l), with low phosphate 0.63mmol/l (0.8-1.5mmol/l), elevated PTH 173.9pmol/l (1.95-8.49pmol/l), 25-OH vitamin-D 40nmol/l (50-374nmol/l), eGFR 66mls/min, ALP 235U/L (30–130U/l). 24-hour urine calcium was raised 11.3mmol/day (2.5–7.5mmol/day). QT interval was normal on ECG. Urinary tract ultrasound did not demonstrate any calculi. Chest X-ray revealed three opacities projected over right lower lung, arising from the anterior ends of the ribs. Subsequent Chest CT showed multiple expansile lytic rib lesions accounting for the x-ray appearance, with metastasis or myeloma as differential diagnosis. Her myeloma screen was negative. The CT scan also detected a soft tissue lesion 17x24x22mm inferior to the right thyroid lobe, which may represent a parathyroid adenoma in the context of Primary Hyperparathyroidism. This nodule was also identified on neck ultrasound. Whole-body FDG PET-CT confirmed the presence of an enlarged right lower parathyroid gland with multiple brown tumours of the skull, appendicular and axial skeletons. Her DEXA scan demonstrated osteoporosis of the radius, T-score -4.9.

Results and treatment: She was initially treated with aggressive fluid resuscitation and intravenous Pamidronate 90mg, following which calcium level decreased to 3.23mmol/l. She was also started on cinacalcet 30mg daily, in response to this calcium began to fall. Subsequent outpatient reviews had led to multiple admissions for intravenous fluids and Pamidronate over a period of three months, proving that she had refractory hypercalcaemia. She underwent right inferior parathyroidectomy whereby the nodule was fully resected. Histological examination was in keeping with an oncocytic parathyroid adenoma, weighing 7 grams. Calcium was normalised at 2.42mmol/l post-operatively and she is recovering well.

Conclusions and discussion: Primary Hyperparathyroidism with end-organ damage is an indication for surgical intervention. In this case, the timing for parathyroidectomy was relatively urgent due to refractory hypercalcemia and intolerance to cinacalcet. Osteitis Fibrosa cystica (Brown tumour) is rare occurring in about 2% of patients with Primary Hyperparathyroidism. We expect that the skeletal lesions will regress with normalisation of PTH and calcium levels.