The Rat Adrenal Medulla. II. Proliferative Lesions

Abstract

Many strains of rats develop spontaneous or drug-induced adrenal medullary proliferative lesions. However, there is often ambiguity about whether the changes observed are hyperplastic or neoplastic and if the term “pheochromocytoma” is appropriate for the lesion in rodents. Various considerations are presented, and the evolution and morphology of the changes are discussed. The lesions are of practical interest because they have at times impeded drug licensing applications.