Human immunodeficiency virus (HIV)-associated central nervous system (CNS) lymphoma is a diffuse, large-cell non-Hodgkin lymphoma of B-cell origin that usually occurs in the brain (rarely in the spinal cord). It is a late complication of HIV infection. Epstein-Barr virus (EBV) is identified in almost all cases. Primary CNS lymphoma accounts for roughly 4% of primary brain tumors and 1% of all non-Hodgkin lymphoma. Toxoplasmosis is the most common central nervous system infection in patients with the acquired immunodeficiency syndrome (AIDS) who are not receiving appropriate...

Patients with the “typical” imaging findings of toxoplasmosis are usually treated empirically for the disease. However, because lymphoma and toxoplasmosis can have very similar imaging appearances, follow-up evaluation is mandatory. The following parameters should be evaluated to assess the changes in the brain: - Distribution - Enhancement - Hemorrhage - Dynamic control after treatment - MR spectroscopy - MRI perfusion

1. Cerebral toxoplasmosis is characterized by the following features: · Multiple mass lesions with surrounding vasogenic edema (T1 – low signal intensity, T2- medium high signal intensity) · «Ring enchancing lesions» · hemorrhage occasionally occurs mostly in periphery of lesion · positive dynamics after adequate treatment (of pyrimethamine sulfadiazine) · MRS: decreased choline (Cho) · MR perfusion: decreased rCBV 2. Primary CNS lymphoma is characterized by the following features: · single lesion (T1 – low signal intensity, T2- medium high signal intensity) · solid enhancement...

Correct interpretation of brain MRI is of great importance in the differential diagnosis between toxoplasmosis and lymphoma in HIV patients, because of the different treatment strategies.

PubMed Central Eccentric Target Sign in Cerebral Toxoplasmosis – neuropathological correlate to the imaging feature. J Magn Reson Imaging. 2010 Jun; 31(6) GG Sharath Kumar, MD,1A Mahadevan, MD,2AS Guruprasad, MD,1Jerry ME Kovoor, MD,1P Satishchandra, DM, Neurol,3Avindra Nath, MD,4Ranga Uday Kumar, PhD,5andSK Shankar, MD Cancer Imaging 7May201 MR imaging features of intracranial primary CNS lymphoma in immune competent patients. AsemMansour, MontherQandeel, HikmatAbdel-Razeq and HussainAliAbu Ali RadioGraphics. Cerebral Toxoplasmosis December 12. Gregory Tse Lee, MD, Fernando Antelo, MD, and Anton A. Mlikotic, MD 1From the Departments of...