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SEER Inquiry System - Report
Produced: 03/02/2026 6:09 PM
Question 20250027
Inquiry Details
References:
#1: Heme & Lymph Manual & DB. November 2024
#2: College of American Pathologists (CAP). Plasma Cell Malignancies, v1.0.0.1
Question:
Reportability/Histology--Heme & Lymphoid Neoplasms: Is a 2024 diagnosis of borderline smoldering multiple myeloma reportable? See Discussion.
Discussion:
Smoldering multiple myeloma is reportable. However, it is unclear if a diagnosis of borderline smoldering multiple myeloma should be accessioned when no further follow-up with the physician is possible. The physician stated the patient, "most likely has borderline smoldering multiple myeloma, but mostly MGUS," and further noted the definition of smoldering myeloma requires at least 10% of plasma cells involved with the neoplasm and some areas of the patient's bone marrow does meet the 10% plasma cell threshold. The physician noted the patient does not need treatment because of the favorable cytogenetics and lack of organ dysfunction.
Should the term "borderline" be ignored and the case accessioned? Or is a borderline smoldering myeloma non-reportable?
Answer:
Update February 2026, note added:
Report this case as smoldering myeloma (9732/3) based on the plasma cell 10% threshold and favorable cytogenetics and lack of organ dysfunction (9732/3). According to the College of American Pathologists Plasma Cell Malignancies Protocol, in order to code smoldering multiple myeloma, both criteria must be met:
• Serum monoclonal protein (IgG or IgA) ≥3gm/dL, or urinary monoclonal protein ≥ 500 mg per 24h and/or clonal bone marrow plasma cells 10-60%
• Absence of myeloma defining events or amyloidosis.
Note: This case was answered by our expert pathologist and applies to this case only. Registrars should not use the plasma cell threshold to determine reportability or histology. The diagnosis must come from the pathologist or the managing physician.
