A Case of T-Cell Large Granulocyte Lymphocytic Leukemia in Rheumatoid Arthritis.

T-cell large granulocyte lymphocytic (TLGL) leukemia is a lymphoproliferative disorder involving clonal expansion of cytotoxic T-cells and subsequent cytopenia, most notably neutropenia, as well as splenomegaly. TLGL leukemia is commonly associated with autoimmune disorders, most commonly rheumatoid arthritis (RA). We present a case of a 54-year-old female with a past medical history of seropositive RA who was lost to follow-up and thus was not on any active treatment for RA for several years. She returned to the clinic with worsening joint pain, swelling, and stiffness involving multiple joints. Screen laboratory work revealed an absolute neutrophil count (ANC) of 0.19 K/uL, indicating severe neutropenia. This finding prompted further workup, for which our patient was ultimately diagnosed with TLGL leukemia. Proper treatment and control of inflammation in RA are important not only to preserve joint function and vitality but also to prevent rare sequela of untreated autoimmune disorders, as was the case in our patient.