Occult manifestations of cancer.

Clinical syndromes occasionally associated with or heralding cancer are summarized and classified.Some tumours present with manifestations of an endocrine or endocrine-like action; included in this group are thymomas, non-beta-cell tumours of the pancreas and carcinoids. Cushing's syndrome, hypoglycemia, hypercalcemia, polycythemia and gynecomastia have been produced by a wide variety of tumours. Tumour emboli, non-bacterial thromboendocarditis and thrombophlebitis occasionally occur, but thrombophlebitis is not so frequent as was previously considered. Neurological syndromes are rare and show a great variety of presentations. Other occult manifestations of cancer include hypertrophic pulmonary osteoarthropathy, various skin diseases, obscure pyrexias and, in Hodgkin's disease, pain secondary to alcohol consumption.