Angiocentric glioma: clinical, morphological, immunohistochemical and molecular features in three pediatric cases.

Angiocentric glioma is a rare slow growing tumor. It is associated to seizures and is mainly diagnosed in children and young adults. We describe the clinical, histo-pathological and molecular (IDH1, IDH2 and BRAFV600E mutational status) features in 3 children, 2 girls (2- and 11-years old) and 1 boy (10-years old). The tumors were located at the left temporo-parietalinsular, left parieto-occipital and left subcortical paramedian region respectively. All 3 patients were operated. Two patients are well at 2 and 16 months of follow-up while the third still suffers from seizures at 7 years of follow-up. Histologically, all tumors were composed of spindle-shaped cells showing a prominent tendency to align around the blood vessels and to grow in the subpia space creating palisade-like structures. In one case the tumoral cells were embedded in a mucoid matrix and some microcalcifications were observed. In all the cases the neoplastic cells diffusely immunostained for GFAP and S-100. Punctate dot-like intracytoplasmic staining for EMA was also observed. All tumors resulted in wild type for the mutations investigated. Owing to the rarity of angiocentric glioma, we believe that each new case should be recorded to produce a better clinical, pathological and molecular characterization of this lesion.

Glioneuronal tumor with neuropil-like islands: clinical, morphologic, immunohistochemical, and molecular features of three pediatric cases.

Glioneuronal tumors with neuropil-like islands are rare. The 1st reported cases were localized in the cerebral hemispheres of adults, showed homogeneous histopathologic features (infiltrating astrocytic growth and neuropil-like islands rimmed by neuronal cells), and had an unfavorable behavior. We report 3 pediatric cases (1 boy and 2 girls, ages 4, 6, and 8 years, respectively). The boy had a cerebral tumor, and the girls had a spinal tumor. The younger girl also had multiple posterior fossa lesions. The boy and older girl underwent a gross total resection. The younger girl underwent a subtotal resection of the spinal tumor; posterior fossa lesions were not surgically treated. The boy and younger girl are in complete remission at 33 and 24 months, respectively, after surgery and subsequent high-dose chemoradiotherapy. The older girl had a recurrence that was partially resected. Afterward, she started high-dose chemoradiotherapy and had an optimal radiologic response at 4 months follow up. Microscopically, the common denominator was the presence of synaptophysin-positive neuropil-like islands. One tumor showed ependymal features (pseudorosettes and punctate epithelial membrane antigen immunopositivity). Two tumors had 1p deletion. 19q deletion, MGMT gene promoter methylation, EGFR amplifications or polysomy, and EGFR, IDH1, IDH2, and TP53 genes mutation analyses yielded negative results. In conclusion, glioneuronal tumor with neuropil-like islands can affect children, arise in the spinal cord, and show ependymal features in its glial component. A high-dose chemoradiotherapy program is effective.

IDH1 mutation in pediatric gliomas: has it a diagnostic and prognostic value?

Mutations in IDH1 gene are observed in gliomas with significant differences according to histotype, grade, prognosis, and age. We analyzed the IDH1 gene mutations frequency in 42 gliomas from 40 children (14 pilocytic astrocytomas; 3 pilomyxoid astrocytomas; 3 diffuse astrocytomas; 1 gliomatosi cerebri; 8 subependymal giant cell astrocytomas; 2 anaplastic astrocytomas; 9 glioblastomas). No IDH1 mutation was detected. Our results indicate that there is no IDH1 gene involvement in the onset and progression of pediatric astrocytomas. We argue that it is not useful in children to assess the status of IDH1 gene nor for diagnostic nor prognostic purposes.