Presentation
Seizure.
Patient Data
A large unusual lesion is present with a large cystic component in the right frontal lobe and a solid, heterogeneously enhancing component extending across the midline via the corpus callosum and bulging into the ventricles. There is only a thin rim of T2 high signal surrounding it, and large areas of the solid component demonstrate signal loss (calcium or blood product).
Case Discussion
This patient went on to have a craniotomy which revealed the lesion to be a pilocytic astrocytoma.
Pilocytic astrocytomas are usually associated with pediatric posterior fossa tumors but can be seen in adults often in unusual locations, and frequently associated with the ventricular system.