Clinicopathologic changes and molecular finding of epithelioid pleomorphic xanthoastrocytoma: a case report

We report a 49-year-old woman who presented with a 4-month-history of headache, nausea, and no epilepsy. Magnetic resonance imaging (MRI) showed a mass in the left temporal lobe region. The edges were unclear, and it was a non-cystic and obvious perifocal edema. The radiologist first considered that it was a high-grade glioma. Macroscopy found that the tumor measured 6.2 cm × 5.2 cm × 5 cm. Microscopy found that the tumor cells were pleomorphic and indicated the presence of many epithelioid/rhabdomyoid cells, multifocal necrosis, and significant bleeding. The distribution of the reticular fibers was segmented, which is difficult to diagnose when it is accompanied by partial anaplastic features. The immunohistochemical makers of the tumor cells were positive for GFAP, Oligo-2, S-100, ATRX, INI1, BRAF (V600E), and P53 but negative for IDH1 (R132H). The tumor cells exhibited a low proliferating index of Ki-67 (< 5%). Molecular pathological detection revealed that the BRAF (V600E) gene was positive, and there was no mutation in the IDH and TERT genes, no 1p/19q-codeleted, and no methylation in the MGMT promoter. The final pathological diagnosis was pleomorphic xanthoastrocytoma (PXA, WHO grade II) with partial anaplastic features. The patient had no additional adjuvant radiation and underwent temozolomide-based chemotherapy. No recurrence was found over a 30-month follow-up. Therefore, the pathological diagnosis combined with the clinicopathological features, histopathological morphology, and related molecular detection is of great significance for the accurate classification, prognostic evaluation, and precise treatment decision for glioma.