Hairy cell leukemia with CCND1/IGH fusion gene and BRAF V600E mutation

Area of Science:

• Hematology
• Oncology
• Genetics

Background:

• Hairy Cell Leukemia (HCL) is a rare chronic lymphoid leukemia.
• Diagnosis typically relies on specific immunophenotypic markers and genetic mutations.
• Co-occurrence of certain genetic alterations can complicate diagnosis and classification.

Purpose of the Study:

• To report a rare case of HCL with concurrent CCND1/IGH translocation and BRAF V600E mutation.
• To discuss the diagnostic implications of this co-occurrence.
• To explore the potential for a new HCL subtype.

Main Methods:

• Peripheral blood and bone marrow examination.
• Flow cytometry for immunophenotyping.
• Fluorescence in situ hybridization (FISH) for chromosomal translocations.
• Polymerase chain reaction (PCR) for mutation analysis.
• Cyclin-D1, Annexin-A1, and TRAP staining.

Main Results:

• Patient presented with pancytopenia and abnormal lymphocytes.
• Flow cytometry revealed monoclonal B-cells with a specific marker profile.
• FISH detected t(11;14) translocation.
• PCR confirmed BRAF V600E mutation.
• Immunohistochemistry positive for cyclin-D1, Annexin-A1, and TRAP.
• Diagnosis of HCL favored due to combined findings.
• Patient achieved complete remission (CR) with cladribine therapy.

Conclusions:

• The co-occurrence of CCND1/IGH and BRAF V600E in HCL is rare.
• This genetic profile may represent a distinct subtype of HCL.
• Further research is warranted to characterize this potential new subtype.