Purpose: There is still some confusion with regard to the tumor-third ventricle floor (3rd VF) relationship of craniopharyngiomas located exclusively within the third ventricle. This study aims to provide some evidence to clarify the growth pattern of intraventricular craniopharyngiomas (IVC), and to summarize the surgical strategy and outcome.
Methods: Seventeen cases of IVC were reviewed retrospectively in relation to preoperative imaging, clinical presentation, intraoperative findings, tumor pathology, and surgical outcome. The tumor-3rd VF relationship and the tumor's stratification were analyzed based on intraoperative inspection and histology.
Findings: Variable adherence patterns of IVC to the 3rd VF were found, which were classified as (a) purely IVC with pedicle attachment to 3rd VF (two cases), (b) intra-3rd VF tumors with wide-based attachment but a dissectible tumor boundary (seven cases), and (c) intra-3rd VF tumors with an undissectible wide, tight attachment (eight cases). Histological analysis revealed that both of the two cases with growth pattern "a" intruded into the third ventricular cavity without a covering layer of neural tissue (which only exists in the squamous-papillary subtype). Tumors with growth pattern "b" and "c," in contrast, were noted to have a thin layer of neural tissue. This occurred in both subtypes (11 adamantinomatous, 4 papillary). Total removal was accomplished in all tumors demonstrating growth pattern "a" and "b." There was also better preservation of the 3rd VF and consequently a better outcome. On the other hand, total removal was only achieved in 50% of tumors showing growth pattern "c" including one mortality. No recurrence has been encountered in patients whose tumors were totally removed.
Conclusion: Variable adherence patterns and tumor subtypes were observed in IVCs, which were correlated to the tumor pathology, resectability, and subsequent prognosis.