ICD-10-CM > C00-D49 > C81-C96 > C90 > C90.3 C90.3 Solitary plasmacytoma Non-Billable/Non-Specific Applicable To Localized malignant plasma cell tumor NOSPlasmacytoma NOSSolitary myeloma Codes C90.30Solitary plasmacytoma not having achieved remissionC90.31Solitary plasmacytoma in remissionC90.32Solitary plasmacytoma in relapse