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| T1 pre-gad | T1 post-gad | T2 |
Diagnosis: Progressive multifocal leukoencephalopathy
Progressive multifocal leukoencephalopathy (PML) is a viral opportunistic infection involving oligodendrocytes which leads to demyelination. The etiologic agent is the JC virus which was named after the initials of the first patient from which the agent was isolated. In the past, PML was more commonly associated with organ transplantation. Now it is usually seen in association with HIV although it may also occur in the setting of organ transplantation, leukemia, and lymphoma as well as inherited immunodeficiency syndromes such as Wiskott- Aldrich syndrome. Patients typically present with progressive cognitive decline often leading to death. When PML was initially described, enhancement was not a feature of the disease. More recently, there have been reports of PML associated with enhancement and mass effect. The disease usually involves the periventricular and subcortical white matter of the frontal or parieto-occipital regions in an asymmetric fashion. A significant minority also have disease in the posterior fossa as well as the corpus callosum, basal ganglia and thalamus. If a patient has the more classic findings of PML, which are asymmetric white matter involvement without enhancement or significant mass effect, the differential is limited particularly if there is a history of immunosuppresion. Other things to consider may include astrocytoma, ischemia, or other demyelinating disease. This patient had known HIV for 4 years and rapidly succumbed from his PML which was the presumptive diagnosis. You may have noticed on the T1 axials post gad the apparent delta sign involving the superior sagittal sinus. This finding is due to slow flow within the superior sagittal sinus since there is a flow void on the T2s and there is phase artifact involving the superior sagittal sinus on the T1 sagittals pre gad. Related Cases Whiteman ML, Post MJ, Berger JR, et al. Progressive multifocal leukoencephalopathy in 47 HIV-seropositive patients: neuroimaging with clinical and pathologic correlation. Radiology, Apr 1993; 187(1):p233-40.
Mark AS, Atlas SW. Progressive multifocal leukoencephalopathy in patients with AIDS: appearance on MR images. Radiology, Nov 1989; 173(2):p517-20.
Guilleux MH, Steiner RE, Young IR. MR imaging in progressive multifocal leukoencephalopathy. AJNR, Nov-Dec 1986; 7(6):p1033-5.
Aksamit AJ Jr. Progressive multifocal leukoencephalopathy: a review of the pathology and pathogenesis. Microscopy Research & Technique, Nov 1995; 32(4): p302-11.
Katz DA, Berger JR, Hamilton B, et al. . Progressive multifocal leukoencephalopathy complicating Wiskott-Aldrich syndrome. Report of a case and review of the literature of progressive multifocal leukoenceophalopathy with other inherited immunodeficiency states. Archives of Neurology, Apr 1994; 51(4):p422-6.
