 There are multiple small nodular areas isointense to gray matter on all sequences along the posterior aspect of the lateral ventricles especially along the occipital horns and atria, consistent with heterotopia. There is decreased lateral ventricular caliber posteriorly due to the intraluminal projection of the nodular heterotopia.There are no diffusion abnormalities. There is no midline shift. There is focal prominence of the extra-axial space along the posterior fossa with mild mass effect on the cerebellum. Midline structures are unremarkable.There is a prominent mildly T1 and prominently T2 hyperintense oval structure in the lateral left frontal sinus.
1. Extensive subependymal nodular heterotopia along the posterior aspect of the lateral ventricles.2. Prominence of the extra-axial space along the posterior fossa, representing incidental mega cisterna magna versus small retrocerebellar arachnoid cyst.3. Probable mucosal retention cyst in the left frontal sinus.