Acute visual deterioration following endoscopic transsphenoidal resection of a pituitary adenoma secondary to a de novo cyst of normal pituitary origin: illustrative case

BACKGROUND: Pituitary adenomas (PAs) are common benign intracranial neoplasms. Transsphenoidal resection is the standard of care for symptomatic tumors, with surgical complications including CSF leakage, infection, hormonal disturbances, and postoperative hematomas leading to visual decline. Rapid postoperative cyst development leading to acute visual deterioration is a rare but potentially significant complication. OBSERVATIONS: A 63-year-old female with headaches and pulsatile tinnitus presented with a large PA compressing the optic apparatus. Transsphenoidal surgery (TSS) via an endoscopic endonasal approach was performed. On postoperative day 6, the patient experienced rapid onset of bitemporal hemianopsia, and imaging revealed a new suprasellar cystic lesion. The patient underwent emergency craniotomy for cyst resection, with pathological analysis demonstrating a nonneoplastic anterior pituitary gland. A systematic literature review of rapid cyst formation following TSS yielded only 1 article for inclusion. No cases of a postoperative cyst of normal pituitary gland origin were identified. LESSONS: Visual decline following TSS is typically due to a sellar/suprasellar hematoma, abscess, or CSF accumulation. Few reports attribute acute postoperative visual deterioration to the development of a secondary pituitary mass, typically due to PA recurrence or formation of a suprasellar cyst. Emergency cyst resection via a transcranial approach resulted in restoration of vision and preservation of pituitary function, supporting aggressive surgical management. https://thejns.org/doi/10.3171/CASE26459.