ICD-10 Code C90 – Multiple myeloma and malignant plasma cell neoplasms (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C90 – Multiple myeloma and malignant plasma cell neoplasms
What it is
C90 identifies malignant plasma cell disorders, including multiple myeloma. These conditions involve abnormal plasma cells that grow in the bone marrow and can damage bone, blood production, and organs.
Clinical signs
Clinical features vary; refer to documentation. Commonly documented findings include bone pain, anemia, recurrent infections, renal impairment, or evidence of plasma cell malignancy on biopsy or imaging.
When to use this code
Use C90 when the provider documents multiple myeloma or another malignant plasma cell neoplasm. It also fits confirmed plasma cell malignancy when the record does not specify a more exact subcategory. Review the note for disease type and site details.
Do not use for
Do not use C90 for benign monoclonal gammopathy, plasma cell dyscrasia without malignancy, or uncertain findings. Check documentation if the record only says suspected, ruled out, or pending workup.
Coding tip
Code to the most specific malignant plasma cell diagnosis documented, and verify whether the provider names multiple myeloma or another plasma cell neoplasm.