CNS LYMPHOMA MIMICKING ADEM

Objective: To report a case of central nervous system Burkitt's lymphoma with an initial presentation mimicking acute disseminated encephalomyelitis (ADEM).

Case: A ten year old previously healthy boy presented with facial palsy, severe headache, focal seizures and rapid visual loss of one month duration. There was no preceding febrile illness, recent vaccination or head trauma. No associated night sweats, or weight loss. On examination, he was in severe discomfort, hypertensive, with the pulse of 65 / minute. He only perceived light and had bilateral papilledema on fundoscopic examination, right sided upper motor neuron facial weakness, and diffuse increase in tone, with hyperreflexia. Brain MRI showed ill-defined patchy bilateral changes within cerebral and cerebellar hemispheres, involving gray and white matter. The corpus callosum, optic tracts, basal ganglia & thlamai were also involved. There was meningeal enhancement as well as significant mass effect in the posterior fossa.

The patient was treated with high dose IV pulse steroids without significant improvement. Cerebrospinal fluid (CSF) study as well as bone marrow aspirate revealed B cell Burkitt's lymphoma. Chemotherapy was initiated, however the patient continued to deteriorate, and passed away within one week.

Conclusion: ADEM remains a diagnosis of exclusion, especially when atypical features are present, such as subacute presentation and lack of response to steroids.

MRI is an essential tool in establishing the diagnosis. The predominance of white matter typically non-enhancing lesions & lack of significant mass effect are more characteristic of ADEM. Although multiple sclerosis remains the main differential diagnosis, viral encephalitis, systemic lupus erythematosis and neoplasms should also be considered, and effort should be made for early referral, and rapid investigation in order to initiate appropriate therapy.