Paraneoplastic vasculitis associated with hairy cell leukemia

Area of Science:

• Hematology
• Oncology
• Dermatology

Background:

• Hairy cell leukemia (HCL) is a rare B-cell lymphoproliferative neoplasm, comprising 2-3% of adult leukemias.
• Skin lesions occur in 10-12% of HCL patients; vasculitis, though uncommon, can precede diagnosis.
• Lymphoproliferative diseases require vigilant monitoring for potential systemic involvement and early diagnosis.

Observation:

• A 54-year-old female presented with constitutional symptoms and a maculopapular rash, accompanied by anemia, leukopenia, and thrombocytopenia.
• Skin biopsy revealed lymphocytic vasculitis with immunophenotypic markers (CD45RO, CD20, DBA44).
• Bone marrow biopsy showed 50% infiltration by lymphoid cells expressing CD20 and DBA-44.

Findings:

• Flow cytometry confirmed HCL by identifying a pathological cell population expressing CD11c, CD19, CD25, and CD103 in bone marrow and peripheral blood.
• The patient achieved a complete response after a single dose of cladribrine, a purine nucleoside analog.
• Hairy cells manifesting as acute vasculitis can be an initial sign of HCL.

Implications:

• Patients presenting with acute vasculitis warrant screening for underlying lymphoproliferative disorders like HCL.
• Early diagnosis and treatment of HCL, particularly when presenting with skin manifestations, improve patient outcomes.
• Cladribrine is an effective first-line therapy for HCL, achieving high response rates.