The Incidence of Metastasis of Malignant Tumors to the Adrenals

The frequency with which adrenal metastases from malignant tumors are observed is striking, in view of the relative infrequency of secondary neoplastic deposits in many larger organs receiving a similar arterial blood supply. This great susceptibility of the adrenals to secondary tumor growth is not generally emphasized in the literature, though in some statistical studies figures are found indicating the predilection of certain tumors for metastasis to these organs. Willis (4) in his monograph on metastatic tumors gives the following figures: In 323 autopsies on patients dying of malignant neoplasms, blood-borne secondary growths were present in the adrenals in 27 (8.3 per cent). Of these, 7 came from carcinomas of the breast, 3 from the lung, 3 from the colon, 2 from the thyroid, and 12 from miscellaneous sources. Willis found the incidence of metastatic growth in the adrenals to be greatest from carcinomas of the lung (20–30 per cent) and from malignant melanoblastomas. Warren and Witham (11) found the adrenals involved in 50 out of 162 cases of malignant tumors of the breast. In their series only the lungs, liver, and bone were more frequently the site of organic metastases. Clark and Rowntree (10) report a series of 25,000 consecutive autopsies done at the Philadelphia General Hospital, in only 2 per cent of which were the adrenals examined histologically. They list 202 neoplasms of the adrenal, benign and malignant, of which 42 were metastatic–16 from the gastrointestinal tract, 8 from the breast, 4 from melanomas, 3 from lung carcinomas, and 3 from epidermoid carcinomas. Ewing quotes Offergeld as finding the adrenals involved in 0.85 per cent of metastasizing carcinomas of the uterus, following the liver, lungs, and kidney. Arkin and Wagner (1) found the adrenals to be involved more frequently than any other organ by metastases of pulmonary carcinoma (43 per cent), but Fried (6) lists the adrenals as following the liver, brain, and lungs as the site of metastases from lung carcinomas. Warren (13) reported the adrenals involved in only 0.2 per cent of malignant neoplasms of the stomach and in 8 of 156 cases of carcinoma of the large bowel, following the liver and lung in incidence of metastases (12). Price (3), reviewing 158 cases of squamous-cell carcinoma, found metastases in 19, with adrenal involvement in only one. Mintz and Smith (2) in 100 cases of carcinoma of the prostate found a single case of adrenal metastasis.