Disseminating anaplastic brainstem oligodendroglioma associated with allelic loss in the tumor suppressor candidate region D19S246 of chromosome 19 mimicking an inflammatory central nervous system disease in a 9-year-old boy.

We report the case of a 9-year-old boy clinically presenting with severe headache, vomiting, head retroflexion, nystagmus, and ataxia. Magnetic resonance imaging showed brainstem enlargement leading to the diagnosis of an inflammatory process. In addition, the clinical picture, a monocytic cerebrospinal fluid pleocytosis with elevated protein and lactate and serum IgM antibodies to Mycoplasma pneumoniae favored this diagnosis. Subsequently, corticosteroid treatment rapidly improved clinical symptoms, and lesions declined in subsequent neuroradiological examinations. However, 2 months later, fulminant disease progression led to brain death. Final neuroradiological examination favored meningoencephalitis. The autopsy revealed brain swelling and brainstem softening with a superficial gelatinous mass extending along the spinal cord. Finally, a disseminating anaplastic oligodendroglioma with allelic loss of the D19S246 tumor suppressor candidate locus of chromosome 19 was diagnosed. To our knowledge, this is the first case of a disseminating anaplastic brainstem oligodendroglioma associated with this specific allelic loss occurring in childhood.