Background: Pituitary carcinomas are rare and aggressive neoplasms that despite current treatment regimens continue to have a poor prognosis. Adrenocorticotrophic hormone pituitary tumors have been shown to alter their clinical manifestations with conversion to Cushing disease and silent types. Case Description: The purpose of this paper is to present the first documented case of an adrenocorticotrophic hormone–secreting pituitary adenoma with Cushing disease that differentiated into a silent corticotroph pituitary carcinoma with metastases to distant sites in the central nervous system. Conclusions: This patient was later treated with radiotherapy, temozolomide, and bevacizumab, with 8 years of progression-free survival.
