Diagnostics of Progressive Multifocal Leukoencephalopathy in A Patient With Concomitant Lymphoma Infiltration of Central Nervous System During R-chop Chemotherapy- A Case Presentation and Review of the Literature. - Diagnostics of Progressive Multifocal Leukoencephalopathy in A Patient With Concomitant Lymphoma Infiltration of Central Nervous System During R-chop Chemotherapy- A Case Presentation and Review of the Literature. - Open Access Pub

Progressive multifocal leukoencephalopathy (PML) is a rare complication associated, inter alia, with rituximab-based lymphoma treatment. PML diagnosis is made easier with the criteria recently published by the American Academy of Neurology. Unambiguous diagnosis of PML can be achieved by demonstration of the histopathological triad comprising:(1) demyelination, (2) bizarre astrocytes and (3) enlarged oligodendroglial nuclei together with detection of viral particles by electron microscopy. However, symptoms of PML may be similar to those observed during lymphoma progression into the central nervous system (CNS). Here we report the case of a patient with diffuse large B-cell lymphoma (DLBCL) treated with R-CHOP who developed clinical signs indicating PML. Intravital diagnostic methods failed to yield an unequivocal diagnosis of PML or lymphoma progression in the CNS. However, a post-mortem examination of brain biopsy specimens performed by electron microscopy demonstrated lesions typical for PML and the presence of viral particles. In addition, immunohistochemical assays identified a massive infiltration of lymphoma cells. The case thus suggests either the extremely rare coexistence of two complications: lymphoma CNS infiltration and PML or induction structural CNS lesions by lymphoma infiltration indistinguishable from PML. The presented findings thus highlight the need for a further review of the current diagnostic criteria for PML. DOI 10.14302/issn.2372-6601.jhor-14-378 Progressive multifocal leukoencephalopathy (PML) is a very rare complication associated with rituximab (R) administration. The first two cases of PML were reported in 2002, however since others also emerged, an additional health warning was included in the summary of R characteristics.1, 2 The incidence of PML is estimated to be ca. 2-2.89 cases per 100,000 patients treated with R per year.3 The underlying physiology of PML has not been fully elucidated. It has been proposed that the development of the disease is a consequence of reactivation of JC polyomavirus in the brain cells, causing their damage and ultimately, in the majority of cases, leading to patient death. JC polyomavirus is a DNA virus first isolated in 1971 from the brain of a patient with the initials J.C. (John Cunningham) suffering from Hodgkin’s lymphoma who died of PML. Anti-JCV antibodies are detected in 66-92% of the adult population, with infection occurring mostly in early childhood. Despite of high JC infection prevalence the incidence of PML is low. The disease usually accompanies conditions involving