ICD-10 Code C91.32 – Prolymphocytic leukemia of B-cell type, in relapse (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C91.32 – Prolymphocytic leukemia of B-cell type, in relapse
What it is
C91.32 identifies a relapse of B-cell prolymphocytic leukemia, a rare mature B-cell leukemia. Use it when the record states the disease has returned after prior remission or treatment.
Clinical signs
Clinical features vary; refer to documentation. Commonly recorded findings may include circulating prolymphocytes, lymphocytosis, splenomegaly, anemia, or thrombocytopenia, but the relapse status must be documented.
When to use this code
Use C91.32 when the clinician documents recurrent or relapsed B-cell prolymphocytic leukemia after prior response or remission. It applies to follow-up encounters where the active disease is again present, not merely historical cancer status.
Do not use for
Do not use this code for newly diagnosed B-cell prolymphocytic leukemia or for remission without relapse. Check documentation if the note only says leukemia history, suspected recurrence, or another leukemia type.
Coding tip
Confirm both the B-cell subtype and the relapse wording in the assessment before assigning C91.32.