Myeloid sarcoma, in relapse

This code signifies a malignant tumor composed of myeloid blasts that arises in an extramedullary site, indicating a recurrence or persistence of the disease after a period of remission. It represents a specific form of acute myeloid leukemia (AML) presenting as a solid tumor outside the bone marrow, which has returned or progressed.

Use this code when documentation clearly indicates a diagnosis of myeloid sarcoma that has recurred or is progressing following prior treatment. This typically applies to patients who previously achieved remission but now show evidence of extramedullary myeloid blast infiltration. Supporting documentation would include pathology reports confirming myeloid sarcoma and clinical notes detailing the relapse status.

• Ensure documentation explicitly states "relapse" or "recurrent" in relation to myeloid sarcoma.
• Do not confuse with initial diagnosis of myeloid sarcoma (C92.30) or myeloid sarcoma in remission (C92.31).
• Always sequence this code after the primary malignancy if the myeloid sarcoma is a manifestation of a systemic leukemia.