ICD-10 Code C90.22 – Extramedullary plasmacytoma in relapse (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C90.22 – Extramedullary plasmacytoma in relapse
What it is
C90.22 identifies an extramedullary plasmacytoma that has returned after prior remission or treatment. It refers to a plasma cell tumor located outside the bone marrow.
Clinical signs
Clinical features vary; refer to documentation. Common findings include a localized soft tissue mass, site-specific symptoms from compression or invasion, and pathology confirming a plasmacytoma outside the marrow.
When to use this code
Use this code when the record clearly states extramedullary plasmacytoma has relapsed or recurred. You should also verify that the lesion is outside the bone marrow and that the provider documents relapse, not initial diagnosis.
If the note only mentions a plasma cell neoplasm or a history of plasmacytoma without current relapse, do not assign C90.22. Check documentation for the current disease status and anatomic site.
Do not use for
Do not use it for newly diagnosed extramedullary plasmacytoma, solitary bone plasmacytoma, or multiple myeloma. If the record is unclear about recurrence, check documentation.
Coding tip
Look for the exact word “relapse” or “recurrent” in the assessment before assigning C90.22.