Ectopic hormone production by tumours. Clinical aspects.

The ectopic production of hormones by tumours is important to appreciate as relevant endocrine features may antedate the appearance of other evidence of the tumour. This possibility should be borne in mind particularly when considering Cushing's syndrome, excessive ADH production or hypercalcaemia and could result in many instances in a quite different approach to further investigation and management. Carcinoma of lung is the commonest underlying neoplasm in several such situations but there are some, such as the hypoglycaemic syndromes, in which the tumour may even be benign.