Pleomorphic xanthoastrocytoma with anaplastic features

Abstract

Objective  To explore the clinical pathological characteristics, immunophenotyping, diagnosis and differential diagnosis and prognosis of pleomorphic xanthoastrocytoma (PXA) with anaplastic features.  Methods  HE staining was used for histological observation. The expressions of glial fibrillary acidic protein (GFAP), vimentin (Vim), CD34, epithelial membrane antigen (EMA), progestrone receptor (PR), neurofilment protein (NF), neuronal nuclei (NeuN), synaptophysin (Syn), Nestin (Nes), S-100 protein (S-100), P53 and Ki-67 labeling index were detected by immunohistochemical method. BRAF mutation was detected by polymerase chain reaction (PCR) amplification.  Results  A 43-year-old male patient presented with repeatedly paroxysmal tic of limbs and disturbance of consciousness. Cranial MRI revealed multiple abnormal signals in left temporo-occipito-parietal lobe and posterior horn of lateral ventricle, with unclear borderline and cystic degeneration. Surgical removal of the lesion was performed. Histologically, the tumor was biphasic. One part was composed of spindle cells arranged in fascicles or as running water, with weird multinuclear giant cells. Abundant vacuolated lipidized cytoplasm could be seen. Mitosis and "map"-like necrosis were noted. Another part revealed the tumor cells were consistent in size and uniform in distribution, with loose background tissue. Immunohistochemistry showed tumor cells were diffusely positive for GFAP, Vim, S-100, Nes, CD34 and P53, and negative for EMA, Syn, NeuN and NF. Ki-67 labeling index was about 15%. Reticular fiber staining showed abundant reticular fibers in the tumor tissue. BRAF mutation detected by PCR amplification was not found.  Conclusions  Classified as grade Ⅱ in the World Health Organization (WHO) classification, the prognosis of PXA is good. A diagnosis of PXA with anaplastic features should be considered when the tumor demonstrates mitotic activity > 5/10 high power field (HPF) and/or areas of necrosis. The differential diagnosis from glioblastoma multiforme and gaint cell glioblastoma should be paid attention, as all of them contain variable numbers of pleomorphic astrocytes, in order to avoid overtreatment.

DOI: 10.3969/j.issn.1672?6731.2015.08.010