A 55-year-old woman presents with splenomegaly and a white cell count of 120,000/µL with predominance of mature lymphocytes. Flow cytometry shows CD5+, CD19+, CD23+, CD20 (dim), surface IgM (dim), FMC7 negative. What is the MOST likely diagnosis?
- A Mantle cell lymphoma — CD5+, CD23 negative, cyclin D1 positive
- B Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) ✓
- C Hairy cell leukemia — CD103+, CD11c+, TRAP positive
- D Marginal zone lymphoma — CD5 negative, CD23 negative
Correct answer: B. Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL)
Explanation
The immunophenotype CD5+, CD19+, CD23+, dim CD20, dim surface immunoglobulin, FMC7 negative is the classic profile for CLL/SLL. Mantle cell lymphoma is also CD5+ but CD23 negative and cyclin D1 positive due to t(11;14). Hairy cell leukemia expresses CD103, CD11c, CD25, and is TRAP positive. Marginal zone lymphoma lacks CD5 and CD23.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.