A distinctive pediatric case of low-grade glioma with extensive expression of CD34.

Abstract

A 12-year-old girl presented with a generalized convulsion. She had regularly consulted pediatricians for an adjustment disorder over the course of 2 years and had experienced a transient episode of unconsciousness without convulsion 5 months earlier. A mental status examination revealed depressed affect, but general physical and neurological examinations were unremarkable. Computerized tomography scans showed a cystic lesion with calcifications in the left temporal lobe (Fig. 1a). A 3.2 9 2.2 cm solid tumor nodule with a unilocular cyst involving the left middle temporal gyrus was detected by magnetic resonance imaging (MRI). The solid tumor nodule was heterogeneously hyperintense on T2-weighted, T1-weighted, and FLAIR images and isointense on diffusion-weighted images with a heterogeneous contrast enhancement (Fig. 1b– d). The patient underwent surgery because of poor seizure control with anticonvulsant drugs, and the nodule was totally resected. The thickened cyst wall was partially removed to preserve the essential language center of the brain. Intraoperative findings demonstrated a gray-pink, soft tumor nodule with a visually indistinct tumor border and yellowish cyst wall. The patient was immediately seizure free, and the mental disorders showed improvement after surgery. MRI at the 6-month postoperative follow-up demonstrated no evidence of tumor recurrence despite receiving no further therapy. Microscopically, the neoplasm was predominantly composed of packed oval or round cells with small nuclei (Fig. 2a–b). Neither mitosis nor significant nuclear atypia were identified in the predominant tumor cells. The tumor border included neurons with prominent nuclei and nucleoli and ample cytoplasm which were relatively well ordered without particular dysmorphism, suggesting entrapped pre-existing elements. The tumor lesion included increased capillaries with nuclear atypia on the endothelial cells, and the surrounding tumor cells demonstrated capillary-like tubule formation (Fig. 2c–d). These findings suggested the possibility of tumor cells converting into tumoral endothelial cells. Scattered calcifications were noted predominantly in the peritumoral region. Necrotic foci were absent. Tumor cells did not extend into the subarachnoid space. Silver staining confirmed the absence of reticulin fibers among the individual tumor cells (Fig. 2e). The tumor was devoid of Rosenthal fibers, eosinophilic granular bodies, and a biphasic compact/microcystic pattern as well as cellular polymorphism and xanthomatous changes, which are the characteristics of pilocytic astrocytoma and pleomorphic xanthoastrocytoma (PXA), respectively. Immunohistochemistry revealed intense immunopositivity for S100, Olig2, MGMT, vimentin, CD34 and nestin on the tumor cells (Fig. 2f–i). The tumor cells showed focally positive for p53, but showed negative for epithelial membrane antigen, asmooth muscle actin, neurofilament, neuronal nuclear antigen, glial fibrillary acidic protein (GFAP), and mutant IDH1 staining (Fig. 2j). Immunostaining with nestin confirmed that the tumor cells infrequently contain cytoplasmic process. The MIB-1 labeling index was 1.1 %. The relatively distinct border between the tumor region and & Masaya Nagaishi nagaishi-nsu@umin.ac.jp