Extramedullary plasmacytoma in relapse

This code signifies a recurrence of an extramedullary plasmacytoma, a malignant proliferation of plasma cells that arises outside of the bone marrow. This condition typically presents as a solitary tumor in soft tissues, often in the upper respiratory tract, and its relapse indicates the return of the disease after a period of remission.

Apply this code when documentation clearly indicates a previously diagnosed extramedullary plasmacytoma has recurred. This is appropriate for patients undergoing treatment for a relapse or for follow-up care where a relapse has been confirmed. Supporting documentation would include pathology reports confirming plasmacytoma and clinical notes detailing the recurrence.

• Do not use this code for initial diagnosis of extramedullary plasmacytoma; use the appropriate code for the initial encounter.
• Distinguish from multiple myeloma, which is a systemic bone marrow disease, even though both involve plasma cell proliferation.
• Ensure documentation specifies "relapse" or "recurrence" to justify using this code.