Abstract: Pituitary adenoma is a common intracranial tumor, and endoscopic endonasal surgery has become one of its primary treatment modalities. Intraoperative magnetic resonance imaging (iMRI) technology can provide surgeons with real-time imaging during surgery, significantly enhancing surgical precision and safety. This case report retrospectively analyzes a case of recurrent pituitary adenoma treated at the Department of Neurosurgery, Huashan Hospital, Fudan University. During endoscopic endonasal surgery, the iMRI revealed residual tumor tissue located above the scar from previous surgery. With the aid of neuronavigation, the surgeon precisely identified and incised the proliferative fibrous tissue that had been misidentified as the diaphragma sellae, successfully removing the concealed tumor and achieving gross total resection. Postoperatively, the patient experienced marked improvement in visual acuity, preserved normal pituitary function, and had no cerebrospinal fluid leakage. Based on this case and relevant literature, this paper discusses the advantages of iMRI in endoscopic endonasal surgery and its potential to improve patient outcomes, aiming to provide reference and guidance for clinical practice.