Pilocytic astrocytomas with leptomeningeal dissemination: biological behavior, clinical course, and therapeutical options.

BACKGROUND: The aim of this case-based update is to discuss the biological characteristics, clinical course, and optimal treatment of pediatric patients harboring pilocytic astrocytomas (PA) with leptomeningeal dissemination (LMD). PAs are well-recognized benign pediatric tumors of the central nervous system (CNS). Despite a favorable outcome in general, in rare cases LMD might occur and contribute to poor clinical course. Localization of the PA in the chiasmo-hypothalamic region seems especially predisposed to LMD. In addition, specific histological features might constitute the potential for subarachnoid metastases. The optimal treatment is still under discussion but studies suggest that chemotherapeutical treatment should be used as first choice therapy in order to avoid or delay radiotherapy. CASE REPORTS AND DISCUSSION: Two cases of subtotally resected chiasmo-hypothalamic PAs with synchronous LMD but with different rates of progression are described. The literature is reviewed and compared with our findings.