MRI diagnosis of intraventricular primary central nervous system lymphoma

Objective: To summarize the MRI appearance of intraventricular primary central nervous system lymphoma (IVPCNL). Methods: MRI of 7 patients with pathological confirmation of IVPCNL was retrospectively analyzed. Results: The lesions were found in the lateral (4) or 4th ventricle (3) with 2 involving the brain parenchyma as well. All 7 masses were solid, isointense on both T₁ and T₂-weighted images with necrosis in 5. Marked contrast enhancement in all lesions without delineation from the choroid plexus (5), and tumor spread along the ventricular wall (5). Reduced diffusion was noted in the tumor on diffusion-weighted imaging in 1 patient. Three lesions were hyperdense on CT with cord-like calcification (1). Conclusion: IVPCNL should be considered in solid intraventricular masses with hyperdensity on CT, T₁ and T₂ isointensity, and marked contrast enhancement close to the choroid plexus and ventricle wall. (authors)