Endocrine Abstracts

A 15-year-old boy presented with a spiral fracture of left tibia and fibula in 1980. Adjusted serum calcium was 3.38 mmol/l. He had biochemical primary hyperparathyroidism and a superior parathyroid adenoma was removed. His calcium normalised and he was well for next 13 years until 1993 when his calcium began to rise with multiple palpable cervical lymph nodes. He underwent extensive neck dissection. Lymph node histology showed metastases from poorly differentiated parathyroid carcinoma. Further imaging revealed liver and lung metastases. He had two courses of radical radiotherapy and pulmonary metastatectomy.

Over the next 13 years, his calcium levels were 3–4 mmol/l despite monthly pamidronate infusions. It only decreased to 3.1 mmol/l when switched to cinacalcet in 2005. Throughout this time, his hypercalcaemia was asymptomatic. He presented in April 2006 with right thigh pain. Plain X-ray showed destructive changes in right femur, shoulder and pelvis. These were reported as skeletal metastases and correlated with increased uptake on 99mTc-medronate bone scan. He had prophylactic palliative nailing to the right femur. However, bone biopsy taken intra-operatively showed osteitis fibrosa cystica. No evidence of skeletal metastasis was found.

There are number of relevant clinical points in this case: (1) Primary hyperparathyroidism in young men raises the possibility of multiple endocrine neoplasia or carcinoma; (2) We are not aware of metastatic parathyroid carcinoma with persisting tumour burden following such an indolent course; (3) Co-existing vitamin D insufficiency was likely with his rampant hyperparathyroidism and possibly contributed to his skeletal deterioration; (4) Osteitis fibrosa cystica is often mistaken for secondary or primary neoplasia; (5) Preventing future fragility fractures may be difficult in this bisphosphonate saturated patient and we had concerns about his femur which underwent palliative nailing. We are sad to report that our patient died earlier this year, 27 years after his first surgery.