Abstract
Large granular lymphocytic (LGL) leukemia is an uncommon clonal lymphoproliferative disorder. Lambert-Eaton Myasthenic Syndrome (LEMS) is a rare neuromuscular autoimmune disease caused by pathogenic autoantibodies targeting the voltage-gated calcium channels (VGCC) on the presynaptic nerve terminal. We here describe the case of a 77-year old patient with LGL leukemia, associated with a seropositive and symptomatic LEMS and a seronegative rheumatoid arthritis. LGL leukemia treatment clearly improved LEMS symptoms, and led to anti-VGCC antibodies value decrease. To our knowledge, this is the first ever described association between LGL leukemia and LEMS.