Oligoastrocytoma (WHO grade 2)


Image 1

Clinical History: 
A 23 year old man presenting with a mass lesion on CT

Oligoastrocytoma (WHO grade 2)

MR Technique: 
Images were acquired at 3 T on a Siemens Tim Trio system. The scans were 2D in type, with a 4 mm slice thickness, scan times of 3:54 and 1:52, FSE and GRE respectively in type, and with TR/TE/TI = 9000/118/2500 for the FLAIR (T2-weighted) scan with fat saturation and 250/2.46 for the FLASH (T1-weighted post-contrast) scan.

Imaging Findings:
A large right frontal intra-axial mass lesion is noted, extending across the midline through the anterior body of the corpus callosum. There is mild local mass effect. The mass is high signal intensity on the FLAIR scan, and relatively homogeneous. There is no abnormal contrast enhancement.
On scans near the vertex, not shown, the mass extended to involve the right frontal cortex. On CT, not shown, there was subtle thinning of the overlying bone. The imaging findings are most consistent with a lower grade glial cell tumor, specifically an astrocytoma or an oligodendroglioma. The latter diagnosis is suggested in part due to the age of the patient and the subtle thinning of the frontal bone (consistent with a long standing lesion).