ICD-10 Code D41.00 – Neoplasm of uncertain behavior of unspecified kidney (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D41.00 – Neoplasm of uncertain behavior of unspecified kidney
What it is
This code identifies a kidney mass or lesion whose behavior is uncertain, meaning it cannot yet be classified as clearly benign or malignant. Use it when documentation specifies the kidney but does not name a side.
Clinical signs
Clinical features vary; refer to documentation. Many cases are found on imaging as an incidental renal mass, and the record may note indeterminate or uncertain pathology.
When to use this code
Use D41.00 when the provider documents an uncertain-behavior neoplasm of the kidney and laterality is not stated. It also fits when imaging or pathology supports a renal lesion of unclear behavior and the chart does not identify right or left kidney. If the record later specifies side, code more specifically.
Do not use for
Do not use this code for clearly benign renal cysts or for malignant kidney tumors. If the documentation names a specific kidney side, do not choose the unspecified code.
Coding tip
Check the report for laterality and final pathology before assigning D41.00.