Neuronal and Mixed Neuronal Glial Tumors

This group comprises rare and slowly growing, relatively benign tumors (grade 1 to 2), affecting chiefly children and young adults. Seizures and symptoms and signs of increased ICP are common clinical manifestations.

Gangliocytoma (grade 1) and ganglioglioma (grade 1, 2) may occur at any site within the CNS, preferably in the temporal and frontal lobes. These tumors are gray, firm, and often cystic. Gangliocytomas are composed of

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Choroid plexus papilloma A. A nut-sized amount of soft, bluish tissue removed from the cerebellopontine angle consists of cuboidal epithelial cells resting on fibrovascular core (extra-cerebral portion of the plexus of the fourth ventricle) (HE). B. Macrosection of a large choroid plexus papilloma in the lateral ventricle (HE).

figure 1 1.23

Choroid plexus papilloma A. A nut-sized amount of soft, bluish tissue removed from the cerebellopontine angle consists of cuboidal epithelial cells resting on fibrovascular core (extra-cerebral portion of the plexus of the fourth ventricle) (HE). B. Macrosection of a large choroid plexus papilloma in the lateral ventricle (HE).

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Choroid plexus carcinoma with extensive dissemination. A. Highly cellular tumor of pleomorphic columnar epithelial cells forming several rows on fibrovascular cores. B. Tumorous infiltration around the cerebellum (HE) and (C) optic nerve (LFB-CV).

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Choroid plexus carcinoma with extensive dissemination. A. Highly cellular tumor of pleomorphic columnar epithelial cells forming several rows on fibrovascular cores. B. Tumorous infiltration around the cerebellum (HE) and (C) optic nerve (LFB-CV).

atypical neoplastic neurons within a fibrillary matrix, whereas gangliogliomas contain a mixture of neoplastic neurons and glial cells, mostly astrocytes. The neuronal components immunoreact for synaptophysin and neurofilament proteins. Calcifications, eosinophilic globules, and perivascular lymphocytic infiltrations are common. Mitoses are rare, and necrosis is absent.

Central neurocytoma (grade 2) is situated in the lateral or third ventricle at the foramen Monro. It is a well-demarcated soft tumor composed of uniformly small neurocytes. Several architectural patterns are distinguished, resembling oligodendroglial and ependymal tumors. Calcifications are common, and hemorrhages may occur.

Dysembryoplastic neuroepithelial tumor (grade 1) is commonly situated in the cerebral cortex—often in the temporal lobe, less often in the cerebellum and pons.

It has a mucinous or gelatinous appearance. It contains neoplastic neurons, astrocytes, and oligodendrocytes arranged in a nodular pattern. Pools of mucin, calcifications, and abnormal blood vessels are present.

Desmoplastic infantile astrocytoma ganglioglioma (grade 1) is a firm cystic tumor in the cerebral hemispheres. Usually, it infiltrates the leptomeninges and becomes attached to the dura. It has neoplastic neuronal and astrocytic elements arranged in a fascicular pattern within a dense reticulin network.

Dysplastic gangliocytoma of the cerebellum or Lhermitte-Duclos disease (grade 1) has neoplastic and maldevelopmental features. Grossly, the folia are thickened and histologically, the granular cell layer is replaced by dysplastic Purkinje cells. It is often associated with malformations, and it is a component of the Cowden syndrome, an autosmoal dominant disorder.

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