Legend Axial T2 and FLAIR images at the level of the cerebral peduncles demonstrates high signal extending from the interpeduncular cistern to the tectum posteriorly and surrounding the aqueduct of Sylvius. This high signal has ill-defined borders, is more prominent on the left, and involves the red nuclei. An axial FLAIR image (upper right) taken through the pons shows high signal in the tegmentum ventral to the 4th ventricle and in the cerbellar vermis posterior to the 4th ventricle.

Legend Left: Axial T1 post contrast images show mottled enhancement of the lesion. Right: Spectrographic analysis of the pontine mass shows an elevated Choline peak. Key words: mri mrs tumor neoplasia

Brain Diagnosis: B-cell lymphoma of the brain stem & pelvis (not shown)