ABSTRACT
Imaging diagnosis of brain neoplasms is based on: location of lesion (supra- versus infratentorial/intra- versus extra-axial); morphological analysis (size, margins, enhancement pattern); and associated secondary changes, like edema, calcification, and hemorrhage. Common tumors of the pediatric age group are choroid plexus papillomas, teratomas, medulloblastoma, craniopharyngiomas, ependymomas, and metastases from neuroblastoma. In metastatic brain tumors and non-infiltrative primary tumors, such as meningiomas, peritumoral edema corresponds to vasogenic edema, where there is leakage of plasma fluid from altered tumor capillaries, but no tumor cells are present. Many non-tumorous lesions can simulate a brain tumor. Magnetic resonance spectroscopy is used in both the diagnosis and evaluation of treatment response of brain tumors. Sellar expansion with the superior extension of the tumor, above the diaphragmatic sella, gives snowman or figure-of-8 configuration (due to constriction by the diaphragma sella) to adenoma. Benign, slow-growing glial-neuronal tumors are common in children and young adults, particularly in the temporal lobes and associated with adjacent cortical dysplasia.
