In patients with a non small cell bronchogenic carcinoma, the detection on a CT scan of a uni or bilateral adrenal gland mass requires determination of its metastatic nature. CT guided needle biopsy (CTGB) is a minimally invasive method and allowed us to achieve this goal. From August 1986 to October 1992, 30 patients underwent such a biopsy. In 14 cases, a metastasis was diagnosed and in 13 cases the mass was benign. There were 3 false negative results. Two of these were rectified: one by a second CTGB and the other by adrenalectomy. Our results showed that CT scan was unable to discriminate metastasis from benign masses. Magnetic resonance imaging (MRI) was used for 11 patients and seemed to be a more accurate method: allowing detection of a pheochromocytoma and avoiding a CTGB which may have been dangerous, predicting the benign nature of some masses when they were iso-intense in relation to the liver on T2 weighted images. Thus, even with the contribution of MRI, in most cases of bronchogenic carcinomas coexisting with an adrenal gland mass, CTGB appeared essential to determine correct therapy: surgery or medical treatment.