What condition is characterized by hypercalcaemia and is frequently linked to malignancy?

The condition characterized by hypercalcaemia that is frequently linked to malignancy is multiple myeloma. In multiple myeloma, malignant plasma cells produce osteoclast-activating factors that lead to increased bone resorption, resulting in elevated calcium levels in the blood. This occurs as a consequence of the breakdown of bone tissue due to the overactivity of osteoclasts, which is stimulated by the pathological processes associated with the malignancy.

Hypercalcaemia in multiple myeloma can lead to a number of symptoms, including fatigue, weakness, kidney dysfunction, and confusion. Clinicians often monitor calcium levels when evaluating patients with suspected or diagnosed myeloma. In contrast, the other conditions listed do not have such a clear and direct association with hypercalcaemia and malignancy. Phaeochromocytoma primarily affects catecholamine levels and does not typically induce hypercalcaemia. Hyperthyroidism can lead to some metabolic changes but is not directly linked to malignancy-related hypercalcaemia. Congenital hypothyroidism does not cause hypercalcaemia and is unrelated to malignancy as well.