Epstein Barr virus (EBV)-associated primary central nervous system lymphoma (ePCNSL) is increasingly recognized in immunocompromised subjects, including patients receiving systemic immunosuppressive therapy. Here, we report the first case of primary CNS lymphoma associated with EBV in a patient with diffuse cutaneous systemic sclerosis (dcSSc) receiving long-term mycophenolate mofetil (MMF).

A 51-year-old female with dcSSc had been on MMF 2 grams daily, which was initiated for a rapidly rising modified Rodnan skin score (mRSS), severe pruritus, and progressive joint contractures. She had an impressive response to this therapy with a significant decrease in her mRSS. Her condition remained stable for the next five years, after which she developed worsening headaches for 2–3 weeks, associated with dizziness, gait instability, and left homonymous hemianopia. MRI scan of the brain revealed a solitary 2.4cm peripherally enhancing right parietal lobe mass. Excised tissue from the right parietal lobe mass showed EBV-associated diffuse large B cell lymphoma. She received four cycles of chemotherapy (high dose methotrexate and rituximab). Currently, her condition is being monitored. Her left homonymous hemianopia persists.

Because of a favorable toxicity profile, MMF is increasingly being used as long-term immunomodulatory therapy for a wide variety of autoimmune disorders. Nevertheless, patients on long-term MMF should still undergo regular CNS surveillance, not only for opportunistic infections but also for opportunistic malignancies such as PCNSL. Progressive focal or non-focal neurological deficits should always raise the alarm. Prompt evaluation and management can prevent irreversible neurological sequelae.