Anaplastic astrocytoma


This case illustrates features of an extensive primary brain tumor on the CT presentation, with the clue being its extension with cortical involvement and expansion. MRI later has confirmed appearances suggestive of a glial series tumor, interestingly showing two different imaging components: the most superior and posterior aspect of the lesion, involving the superior frontal gyrus, has a pattern of a low-grade glioma, with typical appearances of what we could to call "protoplasmic astrocytoma" (no longer an entity since the 2016 WHO review); and the most anterior and medial component show features of a high-grade component: low ADC values and enhancement, likely representing a component of progression to a higher grade tumor. 

Histology has shown that mitotic activity and cellular pleomorphism were present (they are absent in low-grade gliomas) and, unlike glioblastomas, they did not demonstrate necrosis or vascular proliferation. So, instead of calling this tumor a diffuse astrocytoma, it represents an anaplastic astrocytoma