HCL V 165 year old male with skin lesions and easy bruisability on routine lab screening found to have high WBC count (65,000 /ul) and low platelet count. A bone marrow biopsy showed packed marrow and minimal aspirate material obtained.

What's the underlying condition?

  1. Hairy cell leukemia
  2. Chronic myelomonocytic leukemia
  3. Acute myelomonocytic leukemia
  4. Mast cell leukemia


The answer is “A”, Hairy cell leukemia.

Leukemic cells with pale gray-cytoplasm and oval/reniform nuclei are morphologically consistent with hairy cell leukemia (HCL). Bone marrow biopsy is also typical with packed marrow, neoplastic cells with abundant cytoplasm and central oval nuclei (fried-egg appearance). Leukopenia is more common in HCL, however in variant-hairy cell leukemia (v-HCL) high cell counts are not unusual (flow cytometry: CD25dim, CD103+, CD11c+, CD20+, kappa+). Compared to classical HCL, in v-HCL CD25 and CD103 will show variable expression.
1. Grever MR et al. Hairy cell leukemia. Blood Rev. 2014;28(5):197-203.
2. Matutes E et al. Hairy cell leukemia-variant. Best Pract. Clin Hematol. 2015;28(4):253-63

 Contributed by Vishnu VB Reddy, M.D.