Abstract
OBJECTIVE: Optic tract edema (OTE) is a useful finding in the diagnosis of craniopharyngioma (CP). However, the pathogenesis of OTE is not fully understood. In this study, we investigated the presence of OTE depending on the site of origin of CP. METHODS: We reviewed 48 patients with CP who underwent surgical treatment at Juntendo University Hospital between March 2010 and February 2023 and investigated their size, location, presence of OTE, pathological subtypes, and genetic abnormalities. Tumors were classified into four groups based on their origin: retrochiasmatic (RC) type, prechiasmatic (PC) type, intrasellar (IS) type, and intra-third-ventricle (ITV) type. RESULTS: Forty-eight cases were included in this study. The number of cases of RC, PC, IS, and ITV types were 29, 8, 3, and 8, respectively. OTE was shown in 21 cases. Among them, RC type was the most common location (18 cases, 86%) with significant differences. The cystic component of the tumor was in contact with the optic tract in 15 cases, which was more common than the solid component. DISCUSSION: Possible causes of OTE include cytotoxic edema associated with inflammation, angiogenic edema due to leakage of serum components from the tumor, leakage of fluid components from the cyst, and enlargement of the Virchow-Robin space in the optic disc. In this study, many of the cases with OTE have cystic components in contact with the optic tract, suggesting leakage of fluid components from the cyst as the pathogenesis of OTE. The presence of OTE can be a new factor to determine the surgical approach since CP with OTE is thought to extend posteriorly to the optic chiasm. CONCLUSIONS: OTE is often associated with RC type CP and is thought to be caused by leakage of fluid from the cyst.