Posterior fossa calcifying pseudoneoplasm of the central nervous system.

Calcifying pseudoneoplasms of the neuraxis are rare, poorly understood masses that may arise throughout the CNS. Although these lesions are generally considered benign and noninfiltrative, reports exist that document growth of these masses on serial plain radiographs. The authors report a case of a posterior fossa calcifying pseudoneoplasm of the neuraxis demonstrating interval development of peritumoral edema on serial MRI. Their findings suggest that these lesions may sometimes behave in a more aggressive manner than commonly thought.