Different imaging patterns of PCNSL and IVL: A case report

Background: Primary central nervous system lymphoma (PCNSL) is a rare, malignant, non-Hodgkin's lymphoma of the brain, leptomeninges, and rarely the spinal cord. PCNSL has characteristic magnetic resonance imaging (MRI) findings, and effective treatment strategies are available. It is characterized predominately by neurological symptoms, which are caused by tumor infiltration into the nervous system as well as ischemia. Chemotherapy is an effective treatment, if started prior to the ischemic damage. Case presentation: A 62-year-old male patient with PCNSL presented with altered mental status. The initial brain MRI revealed high signal intensity on the T2-weighted images (T2WIs) of the putamen area of the right basal ganglia, and the clinical symptoms improved after steroid administration. However, the symptoms were later deteriorated, we considered the possibility of autoimmune encephalitis and, consequently, conducted an immunomodulatory therapy. In a follow-up brain MRI, enlargement lesions of T2WI in basal ganglia and pons were simultaneously enhanced. Subsequently, the patient's mental status deteriorated to a semi-coma and PCNSL was diagnosed after a surgical biopsy. Chemotherapy was started immediately; however, the patient died. Conclusions: Effective treatments are available for PCNSL and intravascular lymphoma; thus, their prognosis is generally good if they are diagnosed early. Herein, we report the case of a patient suspected with autoimmune encephalitis after brain MRI and treated with immunomodulation therapy. However, PCNSL was confirmed by a surgical biopsy. It is, therefore recommended to consider lymphoma in patients with neurological symptoms that are difficult to localize and rapidly progressive enhancing lesions showing a mass effect on brain MRI.