Surgical cavity dilatation after resection of IDH-mutated astrocytoma of the mesial temporal lobe: illustrative cases.

Background: Space-occupying tumor bed cysts may exceptionally happen after the resection of diffuse low-grade glioma. Their mechanism and management remain debated. The authors report two cases of tumor bed cysts occurring after the resection of a left temporal diffuse low-grade glioma with two different evolutions.

Observations: The first patient showed a spontaneous decrease in the cyst volume and did not report any symptoms. In contrast, the second patient showed a progressive increase in the cyst volume and reported headaches and difficulties in finding words. Endoscopic cyst fenestration was performed and led to symptom relief and normalization of the surgical cavity.

Lessons: A tumor bed cyst is a rare complication of temporal low-grade glioma resection. Its formation is due to entrapment of the choroid plexus in the temporal horn widely opened into the surgical cavity. Endoscopic cyst fenestration should be offered only in symptomatic cases. https://thejns.org/doi/10.3171/CASE23674.