A Case of Progressive Multifocal Leucoencephalopathy Associated with Thymoma (P03.256)

OBJECTIVE: Our objective is to report an unusual cause of immunodeficiency leading to development of progressive multifocal leucoencephalopathy (PML). BACKGROUND: The association of thymoma and immunosuppression is known as Good9s syndrome. Two cases of Good9s syndrome associated with PML have been reported in the literature. Four other reports have associated thymoma and PML without making the connection to Good9s syndrome. We wish to share our experience and bring forward this rare condition to the attention of clinical neurologists. DESIGN/METHODS: We report a case of PML associated with an AB type thymoma. Good9s syndrome was formally identified with immunological testing. RESULTS: A 51-years-old male was admitted to our neurology unit to investigate a rapidly progressive cognitive impairment. Six months prior to admission, the patient underwent the resection of a fortuitously detected type AB thymoma. Since the last four months, his wife noticed progressive behavioral changes. He developed apathy and memory problems. Magnetic resonance imaging (MRI) of the brain showed FLAIR and T2-weighted hyperintensities in the subcortical white matter of both frontal lobes and left parietal area, involving U-fibers. Gadolinium enhancement was not detected. Cerebrospinal fluid analysis confirmed the presence of JC virus, thus corroborating the diagnosis of PML. Investigation for a source of immunodeficiency yielded a negative HIV test, normal liver and kidney function and a normal PET scan. The patient didn9t take any immunosuppressant drug. Immunological testing demonstrated an hypogammaglobulinemia with low IgG and IgM levels along with a dramatic decline of B cells. A diagnosis of Good9s syndrome, a rare combination of B and T cell immunodeficiency in patients with thymoma, was made. CONCLUSIONS: Treatment with mirtazapine, mefloquine and replacement immunoglobulins was started. This patient was eventually discharged home in a stable but unimproved neurological condition. Disclosure: Dr. Hamelin has nothing to disclose. Dr. Frenette has nothing to disclose.