Progressive multifocal leukoencephalopathy associated with systemic lupus erythematosus: longitudinal observation of lymphocytes, JC virus in cerebrospinal fluid, and brain magnetic resonance imaging.

Progressive multifocal leukoencephalopathy (PML) rarely occurs in patients with systemic lupus erythematosus (SLE). This report presents the case of a patient who developed PML due to SLE-associated multiple factors. A 60-year-old woman diagnosed with SLE undergoing multiple immunosuppressive therapies, including azathioprine, presented with cerebral cortical symptoms, lymphocytopenia, and vitamin B12 deficiency and was subsequently diagnosed with SLE-associated PML. We evaluated the cause and disease activity of PML, focusing on the longitudinal assessment of lymphocytopenia, JC virus (JCV) DNA copy number in the cerebrospinal fluid, and magnetic resonance imaging (MRI) findings. Discontinuing azathioprine and initiating alternative immunosuppressive treatments with intramuscular vitamin B12 injections affected lymphocytopenia and disease management. However, despite recovery from lymphopenia and JCV DNA copy number being low, the large hyperintense and punctate lesions observed on the fluid-attenuated inversion recovery (FLAIR) images exhibited varying behaviors, indicating that the balance between contributing factors for PML may have fluctuated after the initial treatment. Clinicians should be meticulous when assessing the underlying pathology of the multifactorial causes of PML due to SLE. The difference in the transition pattern of these lesions on FLAIR images may be one of the characteristics of MRI findings in PML associated with SLE, reflecting fluctuations in disease activity and the progression stage of PML.

Pomalidomide-associated progressive multifocal leukoencephalopathy in multiple myeloma: cortical susceptibility-weighted imaging hypointense findings prior to clinical deterioration.

Although there are several case reports of progressive multifocal leukoencephalopathy (PML) in multiple myeloma (MM), there are few reports of cases associated with pomalidomide. Here, we report the case of a 69-year-old female who had received 41 cycles of pomalidomide and dexamethasone treatment for relapsed/refractory IgG-κ MM presented with right-hand weakness; she was diagnosed as pomalidomide-associated PML. Fluid-attenuated inversion recovery (FLAIR) on admission showed high signals in the bilateral front-parietal lobe white matter, with multiple punctate lesions in the vicinity of the main lesions. These punctate pattern findings on FLAIR were similar to that of natalizumab-associated PML. Susceptibility weighted imaging (SWI) showed hypointense rims within the cortex at unaffected sites, in the initial stages. Subsequently, the clinical manifestations deteriorated, and the FLAIR images showed new hyperintense white matter lesions at the sites where cortical SWI hypointense rims were detected on the initial MRI examination. Our patient's serial MRI findings suggest that cortical SWI hypointense rims appear prior to the visible demyelinating white matter lesions in patients with PML.