Hairy cell leukemia
Signs and symptoms are usually related to underlying cytopenias (anemia, thrombocytopenia, monocytopenia, neutropenia) and splenomegaly, as well as constitutional symptoms (eg, fatigue, weight loss).
Peripheral blood will show cytopenias and/or circulating neoplastic cells, or hairy cells. They are small to intermediate sized lymphoid cells with oval nucleus and abundant pale blue-gray cytoplasm with indistinct outline with varying numbers of projections, imparting a "hairy" appearance.
Bone marrow biopsy will show lymphoid infiltrate made up of hairy cells. Their abundant cytoplasm makes the nuclei widely separated, giving a "fried egg" appearance. Fibrosis is common, and bone marrow aspirates are often "dry taps" because of this.
HCL is an indolent disease. While treatment is not curative, survival with modern therapy is only slightly lower than the general population.
C91.40 – Hairy cell leukemia not having achieved remission
118613001 – Hairy Cell Leukemia
Differential Diagnosis & Pitfalls
Rule out other causes of splenomegaly such as infection, trauma, chronic inflammatory conditions, sequestration of blood cells, or other hematologic disorders (including leukemia or myeloproliferative neoplasms).
Consider myeloproliferative disorders such as:
- Chronic lymphocytic leukemia
- Mantle cell lymphoma
- Marginal zone lymphoma
- Acute myeloid leukemia due to pancytopenia
- Felty syndrome
- Marrow suppression from viral etiologies such as human immunodeficiency virus, cytomegalovirus, or other infection
- Drug-induced pancytopenia (see acquired pancytopenia)