Pleomorphic Xanthoastrocytoma: MRI Characteristics and Clinicopathological Analysis

Bin Ji, Panying Wang, Yanjiao Li, Zhou Li and Yongsheng Zhong

Department of Radiology, General Hospital of Shenzhen University, China
Department of Medical Oncology, Medical College of Shantou University, China
Department of Neurosurgery, Medical College of Shantou University, China

^*Correspondance to: Zhou Li 

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Abstract:

Background: Pleomorphic Xanthoastrocytoma (PXA) is a rare astrocytic tumor, occurring primarily in childhood and adolescence, with relatively favorable prognosis.
Objective: We compared MRI findings and clinical characteristics of PXA with histopathology diagnosis to better understand the diagnosis and prognosis of the tumor.
Material and Methods: MRI findings of 17 patients with histopathologic diagnosis of PXA were retrospectively analyzed and matched with clinical and pathological features.
Results: The clinical presentation of 17 patients generally occurred in children and youths and included epilepsy (n=11), headaches and dizziness (n=7), with bradykinesia (n=6). All tumors were solitary lesion, located in the superficial cerebral cortex. Thirteen tumors were in temporal lobes, with 2 each in the junction between the right parietal and occipital lobe and the junction between the right frontal and parietal lobe. MRI revealed superficial lumps in the brain: 4 were a solid nodule, 8 were a cystic lesion with a nodule, and 5 were a mixed cystic-solid lesion. The tumor margins were well-defined (n=14) or poorly-defined (n=3), with mild (n=5) or no (n=12) peritumoral edema. The tumors were hypointense or isointense on T1-weighted images, and hyper intense or of mixed signal intensity on T2-weighted images. There was moderate (n=5), marked (n=9) or no (n=3) contrast
enhancement in the solid components and mural nodules, with a meningeal “tail sign” (n=0), and the capsule wall of the cyst was either mildly or not enhanced. The solid portions showed slightly hyper intense, isointense in DWI scanning of 6 cases, whereas the Apparent Diffusion Coefficient (ADC) displays slightly hypointense, isointense. The ADC values of the solid portions were higher than contralateral tissue. Histologically, all tumors were classified as World Health Organization grade 2, comprising spindle, multiform giant cells, and foamy cells. No tumor showed necrosis. Irregular mitosis was seen in 2 cases (<5 mitoses per 10 HPF). Immunohistochemistry demonstrated positive staining for Glial Fibrillary Acidic Protein (GFAP), vimentin, and S-100 protein, and 13 cases also showed positive staining for CD34.
Conclusion: Superficial location, solitary and cystic lesion with enhanced solid components and mural nodules were typical MRI features of PXA. MRI is able to well reveal its morphologic features and have important diagnostic value for PXA, combined with advanced imaging technology, such as DWI, and distinctive clinicopathological features as well as positive reaction of GFAP and CD34, which will contribute to improve the diagnosis and prognosis prediction.

Keywords:

Pleomorphic xanthoastrocytoma; Magnetic resonance imaging; Diagnosis; Pathology

Cite the Article:

Ji B, Wang P, Li Y, Li Z, Zhong Y. Pleomorphic Xanthoastrocytoma: MRI Characteristics and Clinicopathological Analysis. Clin Oncol. 2022;7:1901..