Peritumoral Edema Affects the Prognosis in Adult Pleomorphic Xanthoastrocytoma: Retrospective Analysis of 25 Patients.

Abstract

Pleomorphic xanthoastrocytoma (PXA) is a very rare glial neoplasm. The clinical behavior of PXA is not uniform, and the purpose of this study was to investigate the clinical characteristics of adult PXA and identify prognostic factors. Twenty-five patients aged 18 years or older who were diagnosed with PXA between 2002 and 2016 were analyzed. Twenty-one patients (84%) had PXA World Health Organization (WHO) grade II and 4 patients (16%) had anaplastic PXA (WHO grade III). The median overall survival of PXA WHO grade II and III was 97 and 56 months, respectively. The 3-year progression-free survival of PXA WHO grade II and III was 65.1% and 50%, respectively (P= 0.37 and 0.21). Diffusion-weighted imaging, perfusion-weighted imaging, and positron emission tomography findings failed to predict the histologic grade of PXA and recurrence of PXA WHO grade II. Tumor size >40 mm and presence of evident peritumoral edema (ePTE) were prognostic factors for poor progression-free survival (hazard ratios, 4.4 and 15.2, respectively; P=0.03 and 0.01) according to a univariate analysis. In the recurrent and silent PXA grade II groups, ePTE was present in 87.5% and 23.1% of cases, respectively (P <0.01). The clinical and radiologic features of PXA are not uniform. Tumor size and ePTE are possible prognostic factors for adult PXA. Also, peritumoral edema may be associated with recurrence in PXA WHO grade II. PXA showed a high recurrence rate, and thus close follow-up is needed.