In the case of neoplasms of the adrenal glands that are radiologically and clinically unclear, the indications for surgical resection as well as the subsequent clarification of the entity and dignity on the surgical specimen are difficult. The diagnostics of adrenal neoplasms, in particular the clear distinction between an adenoma and a carcinoma are often tricky from the point of view of a pathologist. In the following, not only the problems of classification and the possibilities of diagnostics in pathology but also an overview of the most important differential diagnoses of other benign and malignant tumors of the adrenal cortex and medulla are presented.