ICD-10 Code C79.00 – Secondary malignant neoplasm of unspecified kidney and renal pelvis (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C79.00 – Secondary malignant neoplasm of unspecified kidney and renal pelvis
What it is
This code identifies metastatic cancer involving the kidney or renal pelvis when the primary cancer started elsewhere and the exact kidney/renal pelvis site is not specified. Use it for secondary, not primary, malignancy.
Clinical signs
Clinical features vary; refer to documentation. Patients may have imaging or pathology showing metastatic involvement of the kidney or renal pelvis, sometimes with hematuria, flank pain, or incidental renal masses.
When to use this code
Use C79.00 when the record states secondary malignant disease of an unspecified kidney or renal pelvis and does not name a more specific renal site. It is appropriate when the metastasis is confirmed or clearly documented by the provider. Code the primary cancer separately when documented.
Do not use for
Do not use this code for primary kidney cancer, renal cysts, or benign renal masses. If the chart specifies a different metastatic site or a more exact kidney/renal pelvis location, choose the documented code instead.
Coding tip
Check documentation for the primary malignancy and the exact renal site before assigning C79.00.