Endocrine manifestations of malignancy

Endocrine manifestations of cancer are usually paraneoplastic syndromes (i.e. rare systemic manifestations of malignancy caused by non-mass cancer effects). The pathobiology involves the production of hormone and related substances that act in an endocrine or paracrine manner, resulting in systemic manifestations. Two major mechanisms are observed: ectopic hormone production by non-endocrine organs and direct hormone secretion from endocrine malignancies. The most common paraneoplastic syndromes include hypercalcaemia, Cushing's syndrome and syndrome of inappropriate antidiuretic hormone secretion. These may be the presenting feature of an underlying malignancy. Rarer syndromes result from ectopic production of less frequently observed bioactive proteins (e.g. growth hormone-releasing hormone, human chorionic gonadotrophin, insulin-like growth factors, renin, vasoactive intestinal peptide) and iatrogenic causes. Here, we review the spectrum of common and rare endocrine manifestations of malignancy.