Hypercalcaemia of malignancy

What it is

Malignancy-induced hypercalcemia is hypercalcemia that comes from the malignancy itself. Two mechanisms are proposed for it: paraneoplastic release of PTHrP, and osteolytic metastatic lesions.

Causes and risk

Four routes are separated, each with its own mediator and the malignancies in which it is seen:

• Humoral hypercalcaemia, through PTHrP, in SCC, breast, ovarian and HTLV-lymphoma.
• Local osteolytic hypercalcaemia, through cyto- and chemokine, in breast, MM and lymphoma.
• Vitamin D mediated, through 1,25(OH)2D, in lymphoma.
• Ectopic hormone secretion of PTH, in variable malignancies.

How it presents

The picture is an elderly chronic smoker with abdominal cramps, decreased urine output and constipation, who also gave a history of hemoptysis over months with cough and night sweats that point to the malignancy.