A dual-axis cisternal classification for congenital intracranial cystic lesions: implications for surgical strategy and long-term prognosis.

BACKGROUND: Congenital intracranial cystic lesions-epidermoid, dermoid, neurenteric, Rathke, colloid-encompass a heterogeneous group of entities whose surgical behavior is only partly explained by histology. We propose a dual-axis cisternal topographic model (medial-lateral × dorsal-ventral) to compare surgical outcome in congenital intracranial cystic lesions. METHODS: We retrospectively analyzed 110 patients with histologically confirmed congenital intracranial cysts undergoing surgical resection at a single tertiary center. Each lesion was categorized by cisternal topography in coronal and axial planes, and correlations were assessed between topographic class, surgical parameters, recurrence, and outcomes. Inter-rater reliability of classification was measured using Cohen's kappa. RESULTS: Lesions with complex cisternal topography-defined as extension across dorsal-ventral (multicompartmental, MCL) or combined median-paramedian compartments-showed higher recurrence (42.1% and 50%, respectively; p < 0.001), including late recurrence beyond five years (23.7% and 35%, respectively; p < 0.001). MCL carried greater surgical morbidity: higher rates of subtotal resection (44.7% vs. 8.3%, p < 0.001), prolonged hospitalization, and doubled complication burden (52.6% vs. 25%, p = 0.006). Functional outcomes were poorer in these subgroups (median GOS = 4, IQR: 4-5), and neurological sequelae, particularly cranial nerve VII/VIII deficits and cerebellar signs, were disproportionately more frequent. A strong correlation emerged between cyst topography and histopathology, epidermoids predominating in complex configurations (p < 0.001). Supplementary analyses indicated that although cyst size varied across histological subtypes, it was not associated with recurrence, and in multivariable models cisternal localization remained significant, whereas histology and maximum dimension did not. CONCLUSIONS: Cisternal topography was associated with recurrence, surgical complexity, and postoperative outcome in congenital cystic lesions. Lesions with multicompartmental or midline-paramedian axial spread carry a high-risk profile and warrant extended surveillance beyond five years. This dual-axis anatomical model may inform more tailored operative strategies and long-term follow-up planning, complementing histological diagnosis in modern skull base surgery.