Case Report: Sellar collision tumor consisting of pituitary adenoma and craniopharyngioma, with literature review.

Collision tumors harbor two distinct histological features at the same site, and sellar collision tumors of pituitary adenoma (PA) and craniopharyngioma (CP) are extremely rare. This report presents a 64-year-old female with fatigue, anorexia, palpitations, dizziness, and exertional dyspnea. Examinations confirmed pan-hypopituitarism and life-threatening electrolyte disturbances. Preoperative MRI showed a homogeneous lesion indistinguishable from a standard macroadenoma. She underwent neuroendoscopic transsphenoidal resection. Intraoperatively, the tumor exhibited a fibrous, tough consistency with no discernible boundary between components, resulting in a "blind" resection of the collision pathology. Significant cavernous sinus hemorrhage (800 mL) occurred due to severe adhesion. Postoperatively, hormone replacement therapy was administered, with stable recovery and discharge on day 18. Pathology confirmed a collision of Null-cell adenoma and Adamantinomatous CP. This case highlights the diagnostic pitfall of "occult" collision tumors where imaging and surgical texture fail to differentiate components, necessitating comprehensive immunohistochemistry. Few similar cases have been reported, mostly involving non-functional PA and adamantinomatous CP with diverse pathogenesis hypotheses. This case supplements critical clinical data on diagnosis, surgical management, and prognosis of this rare sellar tumor, highlighting therapeutic considerations for neurosurgery clinicians.