Primary malignant melanoma of the adrenal gland. A report of two cases and review of the literature.

Primary malignant melanoma of the adrenal gland is an established entity despite early doubts. It originates in the adrenal medulla from cells derivative of the neural crest. Because of the high frequency of metastatic involvement of the adrenal by cutaneous and ocular melanomas, rigid diagnostic criteria should be followed. Only four cases of this lesion have been reported since 1946. Review of these four together with the two described in this article shows that primary adrenal melanoma is a highly malignant tumor of middle age that often manifests as a painful flank mass. Distant lymph node metastases can be seen as a presenting sign. Treatment is not effective with a mortality rate approaching 100 per cent within two years. Since the true melanocytic origin of primary adrenal melanoma has not been established and because of the similarity of its pathologic findings with the pheochromocytomas, we believe that adrenal melanoma arises from the pheochromocytes and should be called "melanotic malignant pheochromocytoma."