Lymphomatosis cerebri Presenting as a Recurrent Leukoencephalopathy

Area of Science:

• Neurology
• Oncology
• Radiology

Background:

• A young, immunocompetent woman presented with neurological deficits suggestive of acute disseminated encephalomyelitis (ADEM).
• Initial presentation included ataxia, limb weakness, dystonia, and diplopia, with MRI showing periventricular white matter lesions.
• Treatment with methylprednisolone led to rapid clinical and radiological improvement.

Observation:

• The patient relapsed four years later with fatigue, imbalance, and speech disorder, exhibiting new neurological signs and MRI-visible enhancing white matter lesions.
• The initial diagnosis of recurrent ADEM was questioned due to disease progression and pseudotumoral appearance on MRI.
• Brain biopsy ultimately confirmed primary central nervous system lymphoma (PCNSL) of the lymphomatosis cerebri variant.

Findings:

• Extensive, initially non-enhancing white matter lesions can represent early signs of primary central nervous system lymphoma (PCNSL).
• PCNSL can mimic inflammatory demyelinating diseases like ADEM, posing diagnostic challenges.
• Despite chemotherapy, the patient had a poor prognosis, succumbing to the disease eight months after diagnosis.

Implications:

• This case highlights the importance of considering PCNSL in the differential diagnosis of extensive white matter lesions, even in young, immunocompetent individuals.
• The concept of "sentinel lesions" preceding PCNSL by years is emphasized.
• Early brain biopsy is recommended for persistent or atypical white matter lesions to ensure timely diagnosis and treatment of potentially treatable conditions like PCNSL.