We present two cases of DCAI, with histopathologic, immunohistochemical, ultrastructural, and molecular genetic data, and draw the following conclusions: (1) the diagnosis of DCAI requires a high index of suspicion and immunohistochemical or ultrastructural proof of astrocytic differentiation; (2) the data argue against nosologically equating these tumors with the desmoplastic infantile ganglioglioma, pleomorphic xanthoastrocytoma, or gliofibroma; (3) the components of the extensive tumor basal lamina may be elaborated by the tumor cells themselves and may contribute in an autocrine fashion to the slow growth of these lesions; and (4) if the lack of allelic loss on chromosomes 17p (including the p53 tumor suppressor gene locus) and 10 seen in our cases is found in other cases of DCAI, this may further distinguish the DCAI from other astrocytomas.