Diffuse subependymoma of the bilateral lateral ventricles.

A 55-year-old female presented with a persistent headache in the left parietal region for more than 2 months. Non-contrast computed tomography demonstrated irregular cast-like soft tissue densities along the walls of both lateral ventricles, with a cystic-solid mass located in the anterior horn of the left lateral ventricle. Magnetic resonance imaging findings strongly suggested a subependymoma involving both lateral ventricles. The patient underwent tumor resection, and histopathology confirmed subependymoma (World Health Organization Grade I) with cystic degeneration and hemosiderin deposition. This case is a rare diffuse subependymoma of both lateral ventricles with cystic degeneration and old hemorrhage. The clinical and imaging features are reported as follows.