ICD-10 Code D49.51 – Neoplasm of unspecified behavior of kidney (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D49.51 – Neoplasm of unspecified behavior of kidney
What it is
D49.51 identifies a kidney mass or growth whose behavior is not yet known to be benign or malignant. Use it when documentation describes an unspecified neoplasm of the kidney and further characterization is pending.
Clinical signs
Clinical features vary; refer to documentation. Patients may have an incidental renal mass on imaging, hematuria, flank pain, or no symptoms at all, but the code itself reflects uncertain behavior rather than a confirmed diagnosis.
When to use this code
Use D49.51 when the provider documents a renal neoplasm of unspecified behavior, or when imaging suggests a kidney tumor but the record does not state benign or malignant. It is also appropriate while pathology or specialist review is pending. Code the documented site exactly as written.
Do not use for
Do not use this code for clearly benign renal lesions or confirmed kidney cancer. If the record names a specific benign or malignant neoplasm, choose the more specific ICD-10-CM code instead.
Coding tip
Check the pathology, radiology, and final provider note before assigning D49.51.