Central nervous system involvement of chronic lymphocytic leukaemia with brain and spinal cord infiltration.

We present a case of a patient in her 70s with an 11-month history of Rai stage 1 chronic lymphocytic leukaemia (CLL) who presented to the emergency department with bilateral lower extremity weakness, frequent falls, urinary retention and incontinence worsening for 2 weeks. Whole-spine MRI with and without contrast revealed continuous patchy and confluent enhancement from C1-T10, consistent with lymphomatous infiltration. Lumbar puncture with flow cytometry demonstrated cerebrospinal fluid involvement of CLL. She started on zanubrutinib with an excellent clinical response. Follow-up whole-spine MRI after 12 weeks of therapy revealed resolution of prior areas of abnormal enhancement. Central nervous system (CNS) involvement in CLL is rare and can cause debilitating symptoms. New neurologic symptoms in patients with a known CLL history should prompt investigation to assess for transformation and CNS involvement. Treatment with a Bruton tyrosine kinase inhibitor such as zanubrutinib or a venetoclax-based regimen may be necessary.