Surgical and clinical aspects of cerebellar pilomyxoid-spectrum astrocytomas in children

Abstract

Cerebellar pilomyxoid astrocytomas (PMAs) and intermediate pilomyxoid astrocytomas (IPAs) are collectively called "pilomyxoid-spectrum astrocytomas (PMSAs)." Cerebellar PMSAs are thought to behave more aggressively than pilocytic astrocytomas (PAs). Our objective is to compare PMSAs to PAs in terms of surgical and clinical profiles. This retrospective study included 66 cases (35 males and 31 females) with cerebellar astrocytomas treated between July 2007 and December 2012 at Children's Cancer Hospital Egypt (CCHE 57357) with a mean age of 7 (±1.5) years. Cases were divided into three subgroups as follows: 44 PAs, 10 IPAs, and 12 PMAs. Comparison between all groups was focusing on brain stem invasion, intrinsic necrotic cavitation, extent of resection, recurrence, leptomeningeal dissemination (LD), metastases, need for CSF diversion, and cerebellar mutism (CM). Cerebellar PMAs and IPAs separately and collectively had higher incidence of brain stem invasion, intrinsic necrotic cavitation, tumor recurrence, and LD when compared to PAs (P < 0.001). Gross total resection was 13.6 % in PMSAs versus 90.9 % in PAs (P < 0.001). PMAs had a higher incidence of tumor recurrence than IPAs (66.7 versus 20 %, P < 0.001). Incidence of recurrence in PAs was 9.1 % in partially resected cases. Mean interval to recurrence was 9 (±1.5) months in PMSAs and 42 (±2) months in PAs. Cerebellar PMSAs express an aggressive clinical behavior and impose more operative challenges than PAs. These tumors may represent a clinical spectrum-at its benign end lies PA, while PMA lies at the aggressive end, with IPA lying just behind. Such concepts could be used to guide management in the future.