NCMP-15. MULTIPLE HEMORRHAGIC CNS LESIONS IN A PATIENT WITH RELAPSED SYSTEMIC CHRONIC LYMPHOCYTIC LEUKEMIA

Abstract Although chronic lymphocytic leukemia (CLL) is the most common adult leukemia in Western countries, extramedullary CLL, characterized by the accumulation of clonal B cells outside of blood, bone marrow, and peripheral lymph nodes, remains rare. The central nervous system (CNS) is the most common site of extramedullary CLL involvement. However, clinically significant CLL in the CNS has been reported in fewer than 100 cases in the literature, and its true prevalence remains unknown with variable estimates. CLL in the CNS most often affects the meninges and usually spares the parenchyma unless there is a higher-grade/Richter transformation; in either case, it is typically not hemorrhagic. Furthermore, in the rare cases reported of hemorrhagic intraparenchymal CLL, patients present with isolated bleeding rather than multifocal hemorrhages. We present the case of a 63-year-old patient with multiply recurrent systemic CLL without Richter transformation who developed bilateral infratentorial and supratentorial micro and macrohemorrhages. Histopathology of a lesion showed focal subacute hemorrhage associated with reactive brain parenchyma containing CLL cells, though it was unclear whether the CLL predated the hemorrhage or if the hemorrhage introduced the CLL. Given the patient’s clinical stability, the lesions were ultimately attributed to coagulopathy in the context of CLL with subsequent secondary colonization of the hemorrhage by CLL cells. These lesions completely resolved after the patient underwent CLL-directed therapy three months after symptom onset. This case underscores the importance of considering bleeding risks associated with CLL and demonstrates that addressing the underlying CLL can lead to the improvement in bleeding sequelae.