MRI features and analysis of cystic oligodendroglioma

Objective To investigate the MRI features of cystic oligodendroglioma (COD) and improve the understanding of this uncommon disease. Methods MRI features of 8 cases with oligodendroglial tumors (including 2 cases with oligodendroglial-element dominated oligoastrocytoma) proved by operation and pathology were analyzed retrospectively.All of 8 cases were completely cystic lesions or large cystic lesions with nodules.Before the neurosurgery,7 cases underwent both plain and enhanced MRI scanning and 1 case underwent enhanced MRI scanning. Results Single lesion was detected in each case with COD.The characteristic MRI findings could be listed as follows: (1) lesion with sharp border,most supratentorial; (2) completely cyst lesion or large cyst lesion with nodule; (3) markedly enhanced nodule,mostly well defined; (4) smooth cyst wall without diffusion restriction,mostly without enhancement; (5) homogeneous cyst fluid without diffusion restriction,with high or low signal on FLAIR T 2WI,mostly hyperintense. Conclusions COD is a rare kind of oligodendroglial tumor and hard to diagnose.However,there are some characteristic MRI findings which will help its diagnosis and differential diagnosis. Key words: Oligodendroglioma; Magnetic resonance imaging