Adrenocorticotropic Hormone Secreting Pituitary Carcinoma: Rare, Durable Response to Concurrent Chemotherapy and Reirradiation With a Review of the Literature

Pituitary adenomas (PA) are a common, benign tumor managed with combinations of surgery, radiation therapy, and medication. Although uncommon, there are atypical PA with aggressive behaviors that are refractory to treatment. In rare instances, pituitary tumors can metastasize or spread. These malignant behaving tumors are called pituitary carcinomas (PC). PC is challenging to manage as they metastasize early and have a poor response to treatment. In reported PC cases, malignant transformation of atypical adrenocorticotrophic hormone (ACTH) secreting PA is a common pathogenesis.