Codes / ICD10CM / C91.4

C91.4 Hairy cell leukemia

ICD10CM code

ICD10CM

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Name of the Condition

  • Hairy cell leukemia
  • ICD-10 Code: C91.4

Summary

Hairy cell leukemia is a rare, slow-growing cancer of the blood and bone marrow that affects B lymphocytes. It is characterized by the accumulation of abnormal lymphocytes with hair-like projections on their surface, which can interfere with normal blood cell production. This condition typically progresses gradually and may lead to cytopenias (low blood cell counts) due to bone marrow infiltration.

Causes

The exact cause of hairy cell leukemia is not fully understood, but it involves genetic mutations in B lymphocytes that disrupt normal cell regulation. Contributing factors may include environmental exposures or alterations in immune system function, though specific triggers remain unclear.

Risk Factors

  • Increasing age (most common in adults over 50)
  • Male gender (slight predominance)
  • Family history of hematologic malignancies (less clearly established)

Symptoms

  • Fatigue and weakness
  • Recurrent infections due to low white blood cell counts
  • Easy bruising or bleeding from low platelet counts
  • Abdominal discomfort or early satiety from an enlarged spleen
  • Unexplained weight loss or fever (less common)

Diagnosis

Diagnosis involves a physical examination, followed by blood tests to assess cell counts and identify abnormal lymphocytes with characteristic "hairy" projections. A bone marrow biopsy is typically performed to confirm the presence of hairy cells and evaluate bone marrow involvement. Flow cytometry and immunophenotyping may also be used to confirm the diagnosis.

Treatment Options

Treatment depends on the severity of symptoms and blood cell counts. Options may include targeted therapies (e.g., purine analogs), immunotherapy, or splenectomy in select cases. Monitoring for disease progression or transformation is standard.

Prognosis and Follow-Up

Hairy cell leukemia generally has a favorable prognosis with appropriate treatment, though relapse can occur. Long-term follow-up is recommended to monitor blood counts, assess treatment response, and detect potential complications or disease progression.

Complications

  • Severe cytopenias (anemia, neutropenia, thrombocytopenia)
  • Increased risk of infections
  • Splenic enlargement or rupture
  • Rare transformation to more aggressive lymphomas

Lifestyle & Prevention

No specific preventive measures are known. Maintaining overall health, avoiding known carcinogens, and adhering to recommended screenings may support general well-being.

When to Seek Professional Help

Seek medical attention for persistent fatigue, unexplained bruising or bleeding, recurrent infections, or abdominal discomfort. Prompt evaluation is important if symptoms worsen or new concerning signs develop.

Tips for Medical Coders

Document the diagnosis, including clinical findings (e.g., cytopenias, splenomegaly) and diagnostic methods (e.g., bone marrow biopsy, flow cytometry) to support code assignment. Ensure specificity of the condition and any associated complications for accurate coding.

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