Primary hyperparathyroidism and metastatic carcinoma within parathyroid gland

Involvement of the parathyroid glands by metastatic tumour is rare. In autopsy studies of known cancer patients, it was noted in 0.2–11.9% of individuals.¹ Hypoparathyroidism and hypocalcaemia as a result of parathyroid destruction by tumour is unusual.^2,3 We report a case of hyperparathyroidism due to parathyroid hyperplasia with simultaneous occurrence of metastatic bronchogenic adenocarcinoma to a parathyroid gland.

Case report

A 75-year-old woman was referred with hypercalcaemia. Six months earlier she had presented to an osteoporosis clinic with generalised pain in the upper limbs. She reported anorexia and mild weight loss but was otherwise asymptomatic. Specifically there were no respiratory symptoms. A bone density scan revealed osteoporosis. Routine biochemical investigations revealed hypercalcaemia, raised parathyroid hormone level and normal renal function (table 1). A parathyroid pertechnetate/MIBI subtraction scan suggested the presence of an enlarged left superior parathyroid gland. The patient was a non-smoker and had no significant past medical history. Plain radiographs of the chest and renal tracts taken 6 months prior to surgery were normal. A diagnosis of primary hyperparathyroidism seemed secure and surgical exploration advised. Prior to operation a hard palpable lymph node in the right submandibular region was noted and it was planned to excise this at the same time as neck exploration.

A unilateral left sided neck exploration was carried out using the surgical strategy which we have previously described.⁴ At operation, an enlarged left superior parathyroid gland was identified and removed. A normal sized left inferior parathyroid gland was excised for comparative biopsy and the right submandibular node …