Lymphomatoid granulomatosis (LYG) is a rare, Epstein barr virus (EBV) associated, angiocentric B cell proliferation, which usually involves the lung but may also involve, more rarely, the central nervous system. Its malignant potential is uncertain, and seems to be linked to the number of EBV positive B cells.

We report the case of a 32-years-old patient, with an antecedent of LYG grade 2, involving lung, who presented with a brain mass lesion one year later, which appears to be a grade 1 LYG without systemic lesion associated. Treated with dexamethasone, the patient underwent a rapid clinical recovery as well as a complete radiological response, maintained two years after the diagnosis.

Little is known about LYG affecting the CNS, and even less about the best therapeutic strategy for those patients. A review of the literature has been conducted and a summary of the therapeutic options for this extremely rare disease is presented. This case is unusual, regarding the initial imaging presentation, mimicking a primary aggressive brain tumor. It does also emphasize the fact that aggressive treatment could be avoided for some selected patients.