BACKGROUND Mixed gangliocytoma-adenoma (MGA) is an uncommon tumor found in the sellar region, characterized by both gangliocytic and pituitary adenomatous components. Preoperative differentiation of these mixed tumors from typical pituitary adenomas can be challenging, making thorough histological examination following resection essential for accurate diagnosis. However, the presence of the neural component in the gangliocytoma does not seem to affect its aggressiveness or recurrence risk after surgery. OBSERVATIONS In the present study, the authors report a case of Cushing's disease secondary to a mixed pituitary adrenocorticotropin adenoma coexisting with an intrasellar gangliocytoma. Innovative preoperative C-X-C chemokine receptor type 4 (CXCR4)-targeted positron emission tomography (PET)/MRI and an intraoperative indocyanine green (ICG) fluorescence endoscope were used to localize the pathology. Biochemical remission was achieved after gross-total resection. LESSONS Gross-total resection of the tumor is a curative management strategy for MGAs. MGA should be suspected if the intraoperative frozen section shows gliosis with ganglion-like neurons but not adenomas. Preoperative CXCR4-targeted PET/MRI can help to localize the pathology causing Cushing's disease. An intraoperative ICG fluorescence endoscope can be used to differentiate the pathology from normal gland tissue.