Atypical visual field defect without major compression from an inflammatory Rathke's cleft cyst: illustrative case.

BACKGROUND: Visual field defects are key determinants for surgical intervention in Rathke's cleft cysts (RCCs). While hemianopia and quadrantanopia are typical, atypical visual field defects without cyst enlargement may complicate treatment decision-making. OBSERVATIONS: A 55-year-old woman developed headaches and bilateral paracentral scotoma 1 month after being referred to our hospital for an incidentally detected RCC in the sella, despite no radiographic evidence of cyst growth. Gadolinium-enhanced MRI demonstrated enhancement extending from the cyst wall to the optic chiasm, suggesting inflammatory spread. Endoscopic endonasal surgery to drain the cyst resulted in complete resolution of symptoms. Histological examination confirmed inflammatory cell infiltration of the cyst wall. Follow-up MRI at 2 years postoperatively showed no evidence of cyst recurrence. LESSONS: RCCs can impair vision not only through compression but also, in some cases, via inflammatory involvement of the optic pathways. Even radiographically stable cysts can produce atypical visual field defects, indicative of inflammation. Early recognition of this mechanism is essential for timely surgical intervention and favorable visual outcomes. https://thejns.org/doi/10.3171/CASE25836.