Objective: A young woman presented with marked hyperparathyroidism with post-operative course complicated by hungry bone syndrome and diagnostic and management challenges of ongoing hypocalcaemia with hyperparathyroidism.
Method: ML, a 32-year-old Fijian Indian female, was referred with severe hypercalcaemia, following one-year history of migratory debilitating bone pain. Initial labs showed corrected calcium(C.Ca) 3.17 [2.10-2.60mmol/L], parathyroid hormone(PTH) 305.4 [2.0-6.0pmol/L] and 25-hydroxyvitamin D(25-VitD) of 22 [40 – 80nmol/L]. Acute management included admission for intravenous fluids and bisphosphonates, which normalised C.Ca. A parathyroid SESTAMIBI/CT-SPECT demonstrated a 31x9x33mm soft tissue mass in anterior superior mediastinum with focal uptake at T3. Further CT neck demonstrated 10x5x5mm mass between left common carotid and subclavian arteries.
Results: ML’s surgical resection of the mediastinal mass was immediately complicated by generalised bony pain, pleural effusions and despite aggressive replacement of calcium, marked hypocalcaemia (Day 1 C.Ca 1.99); consistent with an exaggerated “hungry bone syndrome”. ML has been followed closely for on-going optimisation of calcium and vitamin D; three-month labs showed elevated PTH (30.7pmol/L), despite normalisation of 25-VitD (79nmol/L) and improved C.Ca (2.04mmol/L). Her pre-operative DEXA scan showed T-scores: lumbar spine -5.1SD and bilateral femoral necks -5.6SD. A MRI cervical spine demonstrated widespread lytic lesions including, a lesion in the C2 spinous process and posterior pedicles, considered consistent with pathological fracture. Histopathology reported a 70x65x51mm; 41gm mass with no invasive features. Parafibromin was positive, whilst PGP9.5 was negative; other patterns of staining were normal, making HRPT2/CDC73 mutation unlikely.
Conclusion: This case highlights: 1) the diagnostic challenge of marked hyperparathyroidism with a clinical picture suggestive of malignancy, but histological evidence not supporting invasion; 2) the management issues of moderating post-operative severe hypocalcaemia and hungry bone phenomenon; and 3) the on-going diagnostic and management of post-operative hyperparathyroidism with hypocalcaemia. In summary, atypical primary hyperparathyroidism presents unique diagnostic and management challenges.