Prolymphocytic leukemia of B-cell type, in relapse

This code identifies a rare and aggressive form of chronic lymphocytic leukemia (CLL) characterized by a proliferation of prolymphocytes of B-cell origin. It specifically indicates that the disease, after a period of remission, has returned or worsened. This condition is distinct from typical CLL due to its higher prolymphocyte count and more aggressive clinical course.

Use this code when documentation clearly states a diagnosis of B-cell prolymphocytic leukemia and explicitly indicates that the disease is currently in relapse. This typically follows a period of treatment and subsequent remission, with new evidence of disease progression or recurrence. Supporting documentation would include pathology reports confirming B-cell prolymphocytes and physician notes detailing the relapse status.

• Ensure documentation specifies "B-cell type" and "in relapse" to accurately assign this code.
• Distinguish from C91.30 (not in remission) and C91.31 (in remission) based on the patient's current disease status.
• Do not confuse with T-cell prolymphocytic leukemia (C91.4-), as the cell lineage is critical for correct coding.