Hairy cell leukemia in a 51-year-old Syrian male: a case report

Hairy cell leukemia (HCL), a rare B-cell lymphoproliferative disorder, originates from the splenic marginal zone B cell. However, diagnosis can be particularly challenging in resource-limited settings where advanced tests are not readily available. Misclassification may result in non-selective chemotherapy exposure and increased toxicity. Reporting such cases is important to highlight diagnostic challenges in resource-limited countries.

A 51-year-old male presented with abdominal discomfort, weight loss, and fatigue. Examination revealed splenomegaly. Initial evaluation suggested lymphoplasmacytic lymphoma, and the patient received multi-agent chemotherapy (R-CHOP), which was complicated by severe cytopenias. Splenectomy was performed, yielding a spleen weighing 2216 g. Histopathology and immunophenotyping confirmed hairy cell leukemia. Molecular testing for BRAF V600E (the gold standard for diagnosis) was unavailable due to financial and infrastructural restrictions. Treatment was switched to single-agent cladribine, resulting in marked clinical improvement and a significant reduction in chemotherapy adverse effects. Follow-up imaging and blood work revealed that the patient was in complete remission.

In our case, we emphasize the diagnostic challenges of HCL in low-resource environments and clarify how the empirical administration of R-CHOP chemotherapy led to unnecessary toxicity and suboptimal outcomes. Splenectomy played a crucial diagnostic role when bone marrow tests were directional but not conclusive. We provide an extensive review of differential diagnoses, immunophenotypic hallmarks, what lies beyond the BRAF V600E mutation, and therapeutic approaches.

Early recognition of HCL is crucial to avoid delayed optimal therapy and to enhance patient outcomes. This case emphasizes the critical role of morphology and immunophenotyping in confirming HCL, especially in resource-limited countries.