MRI of intracranial subependymomas.

Objective: We report imaging features of two cases of subependymoma, a relatively rare benign intraventricular neoplasm.

Materials And Methods: The first case was a lateral ventricular tumor, which grew to a large size before becoming symptomatic. The second case was a fourth ventricular subependymoma with extensive cisternal spread.

Results: In Case 1, absence of postcontrast enhancement suggested the correct diagnosis. However, in Case 2 heterogeneous enhancement made the diagnosis uncertain. In both cases, pre- and postoperative MRI was superior to other modalities in defining tumor extent and delineating the surrounding anatomy.

Conclusions: Magnetic resonance imaging is the modality of choice for studying subependymomas. The diagnosis should be placed among differential considerations for intraventricular tumors.