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Glioblastoma with primitive neuronal component, a rare neoplasm, is recognized as a distinct histological pattern of glioblastoma. In this study we report the morphological and immunohistochemical features of three cases of glioblastoma with primitive neuronal component diagnosed at the Institute along with a comprehensive literature review. The cases include: (1) 11-year-old girl with right fronto-parietal lesion, (2) 48-year-old male with right parietal lesion, and (3) 36-year-old male with left fronto-parietal lesion. Case 1 had prior history of glioblastoma. All the cases had classic morphology of glioblastoma along with GFAP-negative and synaptophysin-positive primitive neuronal component. The latter was poorly demarcated from the glial component in case 1, while well-defined in the remaining two. All the three cases exhibited diffuse p53 positivity and a higher MIB-1 labelling index in the neuronal component compared to the glial component. One of them (case 3) was IDH1 R132H-mutant with loss of ATRX expression. None were positive for K27M-mutant H3 or G34R-mutant H3.3. Literature review of 50 published cases of glioblastoma with primitive neuronal component was performed. The age of onset ranged from 3 months to 82 years (mean: 50 years) with M:F of 1.5:1. 18.8% of tumors were IDH-mutant, 87.5% were p53 positive and three cases showed H3F3A gene mutations. There was a greater propensity for neuraxial dissemination, noted in 20% of cases. Overall survival of glioblastoma with primitive neuronal component was similar to that of IDH-wildtype glioblastoma (13 months) which was significantly shorter compared to the overall survival of IDH-mutant glioblastoma (33.6 months).

Nonneoplastic epithelial cysts involving the central nervous system are diverse and are predominantly developmental in origin. This study represents a surgical series describing the histopathological features of 507 such epithelial cysts with clinical and imaging correlation. Age at surgery ranged from 7 months to 72 years (mean: 33 years) affecting 246 male and 261 female patients. Colloid cyst was the most frequently resected cyst, followed by epidermoid cyst, arachnoid cyst, Rathke cleft cyst, dermoid cyst, neurenteric cyst, Tarlov cyst, and choroid plexus cyst. Diagnosis was based on the location of the cysts and the nature of the lining epithelium. Rathke cleft cyst showed the highest propensity for squamous metaplasia, significant inflammation, and xanthogranulomatous reaction. Ulceration of lining epithelium and calcification were most frequent in dermoid cyst. Radiopathological concordance was maximal for colloid cyst, followed by epidermoid and arachnoid cysts. Epidermoid and dermoid cysts exhibited the highest propensity for local tumor progression, followed by Rathke cleft cyst.

We describe a case of WHO grade I transitional meningioma with rosettes in a 68-year-old woman. The rosettes were composed of meningothelial cells arranged around dense collagenous cores. Even though the presence of rosettes in tumors of the brain and spinal cord is an indication of neuronal or ependymal differentiation, they are also known to occur in tumors of other lineages. Rosette is an uncommon morphological pattern in meningiomas, with only few cases reported in the literature.

Neurofibromatosis type I (NF1) is a familial tumor syndrome with an autosomal-dominant inheritance. NF1-associated tumors often include neurofibromas, malignant peripheral nerve sheath tumors and pilocytic astrocytomas of the optic nerve. The presentation of NF1 patients with glioblastoma is a rare occurrence, with only a handful of cases reported in the literature. We report two cases of glioblastomas occurring in adults with NF1 and briefly review the relevant literature.

Recently, mutations in IDH1 and IDH2 have been reported as an early and common genetic alteration in diffuse gliomas, being possibly followed by 1p/19q loss in oligodendrogliomas and TP53 mutations in astrocytomas. Lately, IDH1 mutations have also been identified in adult gliomatosis cerebri (GC). The aim of our study was to test the status of IDH1/2, p53 and of chromosomes 1 and 19 in a series of 12 adult and three pediatric GC. For all tumors, clinico-radiologic characteristics, histopathologic features, status of IDH1/2, p53 and of chromosomes 1 and 19 were evaluated. IDH1 mutations were detected only in GC of adult patients (5/12). They all corresponded to R132H. Additional 1p/19q losses were observed in two of them with histological features of oligodendroglial lineage. Other copy number alterations of chromosomes 1 and 19 were also noticed. The median overall survival in adults was 10.5 months in non-mutated GC and 43.5 months in mutated GC. IDH1 mutations were present in GC of adult patients, but not in those of children. There was a trend toward longer overall survival in mutated GC when compared to non-mutated ones. Concomitant 1p/19q loss was observed in IDH1-mutated GC with oligodendroglial phenotype. These observations contribute toward establishing a stronger link between GC and diffuse glioma. In addition, these results also emphasize the importance of testing for IDH1/2 mutations and 1p/19q deletions in GC to classify them better and to allow the development of targeted therapy.