Chronic Lymphocytic Leukaemia: Rare Involvement of the Central Nervous System.

Involvement of the central nervous system, although uncommon, is one of the most frequent extramedullary manifestations of chronic lymphocytic leukaemia (CLL). Various conditions can lead to neurological symptoms in CLL patients and distinguishing between clinically significant CLL involvement of the CNS and other aetiologies can be challenging. The authors report the case of a 90-year-old woman with a previous diagnosis of low-risk CLL who presented to the emergency room with altered mental status. After the most frequent causes were ruled out and considering the underlying disease, CNS infiltration by clonal B-cells was hypothesised and later confirmed. Treatment was initiated, but the patient died soon afterwards. LEARNING POINTS: Central nervous system involvement in chronic lymphocytic leukaemia (CLL) is rare and characterized by a heterogeneous clinical presentation.CNS localisation of CLL should be considered in patients with any neurological symptom, irrespective of the stage and activity of CLL.Brain imaging and cerebrospinal fluid examination should be performed.