Invasive ACTH-secreting pituitary macroadenoma in remission after transsphenoidal resection

RATIONALE: Knosp grade 4 adrenocorticotropic hormone (ACTH)-secreting pituitary adenoma is a rare cause of Cushing disease. After the 1st surgery, the remission rate among these patients is extremely low. PATIENT CONCERNS: We presented a case of a 33-year-old female with classical Cushingoid symptoms. Further investigations revealed ATCH-dependent hypercortisolemia, as well as a Knosp grade 4 pituitary macroadenoma. DIAGNOSIS: Cushing disease, caused by a Knosp grade 4 pituitary macroadenoma. INTERVENTIONS: The patient underwent endoscopic endonasal transsphenoidal surgery with the assistance of intraoperative transsphenoidal Doppler and image-guidance devices. OUTCOMES: Pathologic examinations confirmed that the lesion was an ACTH-secreting pituitary adenoma. The patient was in biochemical remission after surgery. Her postoperative magnetic resonance imaging showed gross-total tumor resection. There was no evidence of recurrence during the 1-year follow-up. LESSONS: With intraoperative Doppler and image-guidance, gross-total resection and biochemical remission can be achieved in Cushing disease when the internal carotid artery is completely encased by the pituitary adenoma.