STAT3 and T-cell large granular lymphocyte leukemia: Notably, T-cell clonality and STAT3 mutations were detected more frequently in spleen samples than peripheral blood or bone marrow from ten atypical LGL leukemia/RA patients with lymphopenia, severe neutropenia, and marked splenomegaly, emphasizing the potential for LGL leukemia misdiagnosis as FS (94).