Desmoplastic infantile astrocytoma (DIA) and desmoplastic infantile ganglioglioma (DIG) (WHO grade I) are large cystic tumors of infants that involve the superficial cerebral cortex and leptomeninges, often attached to dura. DIG contains a variable neuronal component in addition to neoplastic astrocytes. These are rare neoplasms that typically occur within the first 2 years of life. No specific cytogenetics or molecular genetics exist with these types of tumors. Follow-up studies indicate that gross total resection results in long-term survival in patients with DIA and DIG.
Dysembryoplastic neuroepithelial tumor (WHO grade I) is a benign, usually supratentorial, neuronal-glial neoplasm that occurs primarily in children and young adults with a long-standing history of partial seizures. In one study, almost 90% of lesions associated with drug-resistant seizures were found to be dysembryoplastic neuroepithelial tumors. This tumor may develop in any part of the supratentorial cortex, but it has a predilection for the temporal lobe. These types of tumors may occasionally occur in patients with NF1. This tumor carries a good prognosis.
Central neurocytoma (WHO grade II) is composed of round cells with neuronal differentiation. In a large surgical series, incidence ranged from 0.25% to 0.5% of all brain tumors. Almost 75% of these types of tumors are diagnosed between the ages of 20 and 40 years. No specific cytogenetic abnormalities or molecular genetics exist with this tumor. The clinical course of central neurocytoma is benign; the treatment of choice is complete surgical resection. Salvage radiation therapy has been used in patients whose tumors were incompletely resected.
Cerebellar liponeurocytoma (WHO grade I or II), previously called lipomatous medulloblastoma, is a rare cerebellar neoplasm with advanced neuronal/neurocytic and focal lipomatous differentiation. Patients typically present with this tumor during their fifth or sixth decade of life. Cerebellar liponeurocytoma is associated with a favorable clinical outcome.
Paraganglioma (WHO grade I) is a neuroendocrine neoplasm, usually encapsulated and benign, that arises in specialized neural crest cells associated with segmental or collateral autonomic ganglia (paraganglia) throughout the body. Depending on the anatomic location, this tumor is also known as carotid body paraganglioma (chemodectoma) and jugulotympanic paraganglioma (glomus jugulare tumor). An uncommon tumor, paraganglioma typically presents as a spinal intradural tumor in the cauda equina region. Tumors of the carotid body may show familial clustering. No specific cytogenetic abnormalities or molecular genetics exist with this tumor. Tumor location is more relevant than histology in assessing a prognosis; the metastatic rate of para-aortic paraganglioma is high (28%-42%) compared with that of carotid body tumors (2%-9%). Almost 50% of glomus jugulare tumors recur locally; only 5% metastasize.
Ependymoblastoma (WHO grade IV) is a rare, malignant, embryonal brain tumor that occurs in neonates and young children. Ependymoblastomas are often large and supratentorial and generally relate to the ventricles, though they do occur at other sites. These types of tumors grow rapidly, with craniospinal dissemination, and have a fatal outcome within 6 to 12 months of diagnosis.