Abstract General Information

Title

CNS Intravascular Large B-Cell Lymphoma mimicking acute neurovasculitis: a case report with autopsy and review of the literature

Case Presentation, Discussion, and Final Comments.

A 55-year-old male was admitted to the hospital due to unprecedented seizures. Except for vertigo and mild cognitive impairment for two months, his previous clinical history was unremarkable. Brain MRI disclosed signal abnormalities in multiple periventricular areas. CSF analysis showed a slight increase of lymphocytes. Blood, serologies (HIV, hepatitis) and cultures were unremarkable. Since ADEM was initially suspected, pulses of methylprednisolone, plasmapheresis and human immunoglobulin were prescribed. As brain lesions persisted and the cognitive symptoms had worsened, a clinical hypothesis of CNS vasculitis was made and a stereotactic biopsy of a left parietal lesion was performed. Unfortunately, the patient expired few hours after the biopsy due to extubating failure and a necropsy was requested. Histological examination of the surgical specimen showed diffuse brain parenchyma edema and few inflammatory cells. However, it was seen aggregates of pleomorphic and large sized cells confined to cerebral blood vessel lumen. These cells showed strong immunohistochemical expression of CD20, CD79a, PAX5 and MUM1. The Ki-67 labeling index was higher than 95%. Therefore, the final diagnosis was CNS intravascular large B-cell lymphoma, non-germinal center type. On postmortem examination, besides heavy lungs that drained serohemorrhagic fluid, cardiomegaly (480 g) and a diffluent spleen (520 g), a massive brain edema (1,486 g) was observed. At neuropathology examination, small and irregular white matter lesions at periventricular region with small watershed cortical infarctions were observed besides the area from the previous biopsy. Microscopically, an intravascular large B-cell lymphoma was seen within the brain vasculature (CNS-IVLBCL) without evidence of neoplastic cells in other organs. CNS-IVLBCL is a very rare type of cerebral lymphoma with few autopsy reports. It is postulated that the absence of CD29 (1 integrin subunit) and CD54 (ICAM) by tumor cells underlie their inability to migrate transvascularly. The prognosis is poor and the median patients’ age is 70 years (34 – 90 years), with no sex predilection. The differential diagnosis with encephalitis and vasculitis can be difficult because the overlapping of clinical and radiologic features. The gold standard for diagnosis is the brain biopsy in suspicious cases, not infrequently, belatedly and only after excluding neuroinfections, vasculitis or demyelination diseases, as seen in the current case.

Keywords

CNS intravascular lymphoma; Non-Hodgkin lymphoma; Large B-cell lymphoma; Autopsy; Case report