C91.10

HCC Category Mapping

What This Code Means

A slow-growing blood cancer of B-cells that has not responded to treatment or achieved remission.

Coding Tips

• •Chronic lymphocytic leukemia (CLL) is primarily an adult cancer; verify B-cell type is confirmed by pathology
• •This code indicates active disease without remission; document treatment attempts and response

Clinical Significance

Chronic lymphocytic leukemia of B-cell type (B-CLL) is the most common adult leukemia in Western countries, characterized by progressive accumulation of monoclonal B lymphocytes in blood, bone marrow, and lymphoid tissues. The 'not having achieved remission' status indicates ongoing active disease requiring continued monitoring and potential treatment escalation. This diagnosis carries significant implications for immunosuppression, infection risk, and potential transformation to aggressive lymphoma (Richter syndrome).

Documentation Requirements

• ✓Documentation must include the confirmed B-cell immunophenotype (typically CD5+, CD19+, CD23+), the current disease status explicitly stated as not in remission, and the basis for that determination (e.g., persistent lymphocytosis, bone marrow involvement).
• ✓Treatment history and response assessment should be documented, along with current disease stage (Rai or Binet staging system).

Commonly Confused Codes