A Rare Case of Dual Clonal B-Cell Hairy Cell Leukemia: Diagnostic Challenges.

BACKGROUND

Hairy Cell Leukemia (HCL) is a rare chronic B-cell disorder characterized by cytopenia, splenomegaly, and bone marrow infiltration. A 42-year-old female presented with gingival swelling and bleeding, later diagnosed with HCL involving lymph nodes, liver, and spleen.

METHODS

The patient underwent blood tests, PET-CT, bone marrow flow cytometry, biopsy, and lymph node as-piration, confirming HCL. Notably, flow cytometry revealed dual clonal B-cell populations, both CD5-negative and CD10-negative. Immunohistochemistry showed positive B-cell markers (CD20, CD23) and BRAF-V600E mu-tation. Cladribine chemotherapy began on April 18, 2022, followed by supportive treatment.

RESULTS

Blood tests showed pancytopenia, and PET-CT indicated lymph node, spleen, liver, and bone marrow involvement. Bone marrow biopsy confirmed HCL with fibrosis. The patient experienced bone marrow suppression during chemotherapy and received supportive care, eventually leading to a successful discharge.

CONCLUSIONS

HCL is a rare B-cell malignancy causing pancytopenia and organ involvement. The identification of dual clonal B-cell populations is crucial for accurate diagnosis. Early diagnosis and cladribine chemotherapy are effective. Immunohistochemical and genetic testing are key for diagnosis and treatment planning.