Tumor at inferior colliculus causing unilateral tinnitus

Abstract

Central nervous system diseases usually do not cause auditory symptoms because the cen­tral auditory pathway consists on a network of crossed connections between the different nuclei that form it. In addition, we must consider that a small lesion might extend to more than one structure producing many neurologic symptoms due to the proximity of tracts and nuclei in the midbrain. Unilateral circumscribed lesions at inferior colliculus are rare. Ne- vertheless, lesions at this location causing auditory symptoms have been described. Because of the crossed central auditory pathway, the most commonly detected auditory symptoms specifically affected the ability to locate sound or verbal comprehension. We present the case of a 44-year-old man with a long-term monoaural right-sided tinnitus without other comp- laints who was diagnosed of a tumour at right inferior colliculus by neuroimaging. Clinical and radiological findings of this case are discussed.