A diverse group of lesions can involve the tectal region of the brain.
Enhancement is generally minimally or absent in small lesions.
These tumors originating in the quadrigeminal plate may completely obliterate the aqueduct causing hydrocephalus. A solitary, deep intraaxial mass with signal similar to that of brain that shows intense and uniform enhancement and minimal edema should suggest diagnosis of lymphoma. Hydrocephalus due to an aqueductal lesion may cause the tectum to appear short and thick. Distinction of compressed tectum from tectal astrocytoma can be difficult, particularly because astrocytomas in this region are generally low grade and small lesions often do not enhance. Very rarely gliomas develop from astrocytes within the pineal gland itself.