Brain Pathology Case of the Month - March 2013

Contributed by Eytan Raz1 MD, Manila Antonelli2 MD, Luca Saba3 MD, Francesca Caramia1 MD, Pier Luigi Di Paolo1 MD
      Luigi Bozzao1 MD, Felice Giangaspero2 MD, Marco Fiorelli1 MD
1Neuroradiology Unit, Department of Neurological Sciences, Sapienza University of Rome, Italy
      2Department of Pathology, Sapienza University of Rome, Italy
     3Department of Science of the Images, Azienda Ospedaliero Universitaria di Cagliari, Cagliari, Italy.


The patient is a previously healthy 29-year-old man who was admitted to our hospital for evaluation after experiencing seizures. A neurological examination elicited no abnormalities. CT and MR imaging were performed and revealed a cortico-subcortical lesion mass involving most of the right frontal lobe with sulcal effacement, compression on the foramen of Monro and hydrocephalus. The CT demonstrated curvilinear narrow calcifications (Figure 1). The lesion was hyperintense to the cortex on T2 and FLAIR (Figures 2 and 3) while partially hyperintense on T1 (Figure 4), with a marked homogeneous enhancement (Figure 5). All the sequences showed a "bag-of-worms sign" (which is best seen on the T2-weighted images) due to the presence of multiple tiny vessels associated with flow-voids (Figures 2 and 3). Moreover, in the lesion there were two deeply seated pseudocysts that showed contrast enhancement visible in the late phase. Based on these findings, a digital subtraction angiography (DSA) was performed which confirmed the hypervascular nature of the lesion but it did not indicate the presence of an arteriovenous malformation (Figure 6). At surgery, the lesion was removed via a right frontal craniotomy. The excision was macroscopically complete.


H&E stains showed a highly cellular neoplasm composed of uniform and monomorphic neoplastic cells; the nuclei were round and perinuclear halos were present (Figure 7). Numerous calcification were present in the midst of the tumor (Figure 8). The neoplasm showed delicate capillaries disposed in a chicken-wire pattern and above a diffuse hypertrophic vasculature (Figure 9). There were some foci of necrosis with areas of vascular proliferation (Figure 10). Immunohistochemistry evaluation demonstrated positivity for IDH1 antibody demonstrating the presence of an IDH1 (R132H) mutation (Figure 11). What is the diagnosis?


International Society of Neuropathology