Looks like hairy cell leukaemia to me...
The correct answer is option 3. Hairy cell leukemia.
The combination of neutropenia, thrombocytopenia, marked monocytopenia, splenomegaly, absence of lymphadenopathy, and a dry bone marrow aspirate is highly suggestive of classic hairy cell leukemia (HCL).
Cytopenias result from bone marrow infiltration and fibrosis, which commonly causes a dry tap. Marked monocytopenia is particularly characteristic of HCL, while splenomegaly without significant lymphadenopathy is a typical clinical pattern. Diagnosis should be confirmed by bone marrow biopsy, flow cytometry, and BRAF V600E testing. The presence of a BRAF V600E mutation supports the diagnosis of classic HCL and helps distinguish it from several HCL-like disorders.
CLL is unlikely in the absence of lymphocytosis, whereas myelodysplastic syndrome and T-cell large granular lymphocytic leukemia do not typically produce this combination of findings.
Reference:
The combination of neutropenia, thrombocytopenia, marked monocytopenia, splenomegaly, absence of lymphadenopathy, and a dry bone marrow aspirate is highly suggestive of classic hairy cell leukemia (HCL).
Cytopenias result from bone marrow infiltration and fibrosis, which commonly causes a dry tap. Marked monocytopenia is particularly characteristic of HCL, while splenomegaly without significant lymphadenopathy is a typical clinical pattern. Diagnosis should be confirmed by bone marrow biopsy, flow cytometry, and BRAF V600E testing. The presence of a BRAF V600E mutation supports the diagnosis of classic HCL and helps distinguish it from several HCL-like disorders.
CLL is unlikely in the absence of lymphocytosis, whereas myelodysplastic syndrome and T-cell large granular lymphocytic leukemia do not typically produce this combination of findings.
Reference:
- Zent CS, et al. Updated consensus guidelines for the diagnosis and management of patients with HCL and HCL variant. Blood. 2026 Jul 2;148(1):31-42.
- Falini B, Tiacci E. Hairy-Cell Leukemia. N Engl J Med. 2024 Oct 10;391(14):1328-1341.
- Wotherspoon A, et al. Bone marrow and splenic histology in hairy cell leukaemia. Best Pract Res Clin Haematol. 2015 Dec;28(4):200-7.
