Small Lymphocytic Lymphoma Presenting As a Paraneoplastic Syndrome With Acute Central Nervous System Demyelination

Chronic lymphocytic leukemia (CLL)/small lymphocytic lym-phoma (SLL) is a mature B-cell neoplasm characterized by accu-mulation of functionally incompetent clonal lymphocytes with thesame morphologic and immunophenotypic features. CLL and SLLhave the same cellular basis but SLL lacks significant peripheralblood (PB) lymphocytosis. CLL is the most common leukemia inthe United States, accounting for 30% of all leukemias, and SLLaccounts for less than 5% of all non-Hodgkin lymphomas. Themedian age at diagnosis is 65 years, and there is a Caucasian malepredominance.