Sternberg's canal defect: meningitis as the initial presentation in a patient with choroid plexus cyst incidentaloma. Illustrative case.

backgroundCSF rhinorrhea reflects an abnormal communication between the subarachnoid space and the sinonasal tract, most often after trauma or surgery; spontaneous leaks are uncommon and may arise from congenital skull base defects such as a persistent Sternberg's canal. However, its prevalence is debated due to the variability of reported anomalies across different case series in the literature. OBSERVATIONS: A 43-year-old man presented with bacterial meningitis and was incidentally found to harbor a third ventricular choroid plexus cyst with mild ventriculomegaly. He underwent interhemispheric transcallosal resection with external ventricular drain placement. Postoperatively, transient CSF rhinorrhea occurred. CT cisternography localized the leak to a lateral craniopharyngeal (Sternberg's) canal. The defect was repaired through a minimally invasive mini-pterional subtemporal approach with intraoperative neuromonitoring. Symptoms resolved. LESSONS: This case underscores the need to consider occult skull base defects in patients with meningitis and raised intracranial pressure (ICP) and to perform targeted imaging (CT cisternography) when rhinorrhea occurs. When the bony defect is lateral or high flow, a transcranial route may be appropriate; endoscopic options should be weighed based on location and surgeon expertise. Meticulous ICP management may mitigate dehiscence risk. https://thejns.org/doi/10.3171/CASE24644.