Calcifying pseudoneoplasm of the inferior colliculus: an unusual location for a rare tumor: case report.

Abstract

Quadrigeminal plate lesions are rare and usually present with a silent clinical course. Tumors, vascular lesions, inflammatory and infectious processes have been described in this region. Calcifying pseudoneoplasms, also reported as fibro-osseous lesions, cerebral calculi, and brain stones, are unusual lesions in the central nervous system. They can be revealed by cranial radiography, computed tomography, and magnetic resonance imaging as calcified masses and should be differentiated from neoplastic, inflammatory, and vascular lesions. To the best of our knowledge, the occurrence of a calcifying pseudoneoplasm located at the quadrigeminal plate has not yet been reported. A 67-year-old woman with a 6-month history of several daily attacks of dizziness presented to our service. Magnetic resonance imaging studies revealed a tumor in the right inferior colliculus. This lesion was isointense on T1-weighted imaging, hypointense on T2-weighted imaging, and homogeneously enhanced with contrast. The lesion at the quadrigeminal plate was completely removed, and the patient was successfully treated without any new neurological deficit. At the time of follow-up, all preoperative symptoms had resolved. We report the first case of a calcifying pseudoneoplasm of the inferior colliculus. Complete surgical removal of this type of tumor is feasible. We propose surgical treatment in this location when this tumor becomes symptomatic.