Abstract

Alireza Arabestanino39992*, Arman Ai39993 and Hasti Jalali39994

Neoplastic transformation occurs in all glial cell types of the human nervous system, producing a wide variety of clinic-pathological entities and morphological variants. As the molecular events responsible for astrocytoma formation and progression are being clarified, it is becoming possible to correlate these alterations with the specific histopathological and biological features of astrocytoma, anaplastic astrocytoma and glioblastoma multiforme (Sonoda Y, et al., 2001). Diagnosis, treatment, and prognostication in brain stem astrocytomas have been hindered by the occurrence in the same site of two distinct pathological entities-fibrillary and pilocytic astrocytoma. The small size of the specimens from this region adds an additional confounding factor in tumor classification. Nevertheless, histological assignment to either of these two prognostically different categories is often possible, especially if the importance of this distinction is recognized. In the face of a nonspecific histological diagnosis, e.g. "low-grade astrocytoma', certain radiographic and clinical features may, in combination with the pathological findings, be useful in tumor sub classification.