Differential Diagnosis for Progressive Neutropenia with Large Granular Lymphocytes
- Single most likely diagnosis
- T-cell Large Granular Lymphocyte (LGL) Leukemia: This diagnosis is most likely due to the presence of abnormal T-cell populations detected by flow cytometry and gene rearrangement studies, which are supportive of LGL leukemia. The morphologic predominance of large granular lymphocytes and the absence of immature leukocytes further support this diagnosis. Progressive neutropenia is a common feature of T-cell LGL leukemia.
- Other Likely diagnoses
- Felty's Syndrome: Although less common, Felty's syndrome (a complication of rheumatoid arthritis characterized by neutropenia, rheumatoid arthritis, and splenomegaly) could present with similar findings, including neutropenia. However, the presence of abnormal T-cell populations would need to be explained by another mechanism.
- Chronic Lymphoproliferative Disorder of NK Cells: This rare disorder could present with large granular lymphocytes and neutropenia. However, the T-cell origin of the abnormal population in this case makes T-cell LGL leukemia more likely.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Large Granular Lymphocyte Leukemia with Associated Hemophagocytic Lymphohistiocytosis (HLH): Although rare, the development of HLH in the context of LGL leukemia is a medical emergency that requires prompt recognition and treatment. HLH can cause rapid deterioration and death if not addressed.
- Severe Chronic Neutropenia due to Autoimmune Disorders: Autoimmune neutropenia can be associated with various autoimmune disorders. While the presence of abnormal T-cells points towards LGL leukemia, an autoimmune cause of neutropenia should not be overlooked, especially if there are other autoimmune symptoms or signs.
- Rare diagnoses
- Aggressive NK Cell Leukemia: This is a rare and aggressive form of leukemia that could present with large granular lymphocytes and neutropenia. However, it typically has a more aggressive clinical course and different immunophenotypic features compared to T-cell LGL leukemia.
- Adult-Onset Asthma with Eosinophilia and Neutropenia: This rare condition could potentially present with neutropenia but is less likely given the specific findings of abnormal T-cell populations and the morphologic predominance of large granular lymphocytes.