Refractory hypercalcaemia. Parathyroid adenoma or multiple myeloma?

A case of multiple myeloma in which hypercalcaemia persisted despite an otherwise good response to conventional treatment is described. The hypercalcaemia was eventually found to be due to a parathyroid adenoma. Despite the frequent association of hypercalcaemia and malignant disease, and the relative frequency of primary hyperparathyroidism as a cause of hypercalcaemia, there are very few reports of multiple myeloma and parathyroid adenoma occurring together. This case emphasizes the need to be aware that there may be more than one cause of hypercalcaemia in a patient with multiple myeloma.