A 68-year-old man, with a history of pituitary surgery and radiation therapy for pituitary macroadenoma 20 years earlier, presented with a pituitary mass and enlarging lesions within the posterior fossa and spinal canal. Biopsy revealed low-grade pituitary carcinoma. PET/CT scan showed multiple foci of increased Ga DOTATATE activity including pituitary and posterior fossa lesions. After 3 fractions of Lu DOTATATE therapy, the tumor remained stable over 4 years on MRI and Ga DOTATATE scans. This case illustrates the benefit of Ga DOTATATE PET/CT in malignant pituitary disease to assess potential for somatostatin receptor therapy with Lu DOTATATE and monitor treatment.