C65 (Malignant neoplasm of renal pelvis) compared with D41.1 (Neoplasm of uncertain behavior of renal pelvis), from the official CMS tabular data. C65 and D41.1 name the same anatomical site (calyx) with a different neoplasm behavior. MedCoder-derived
Same anatomical site, different neoplasm behavior.
Same site — uncertain behavior (calyx)
The behavior documented for the site — malignant primary, secondary, carcinoma in situ, benign, uncertain or unspecified — decides which column of the neoplasm table, and therefore which code, applies.
Source: CMS Table of Neoplasms
Same site, different neoplasm behavior. C65 and D41.1 name the same anatomical site (calyx) with a different neoplasm behavior.
From the CMS/CDC Table of Neoplasms: the behavior documented for that site — malignant primary, secondary, carcinoma in situ, benign, uncertain or unspecified — decides which column, and therefore which code, applies.
| C65Malignant neoplasm of renal pelvis | D41.1Neoplasm of uncertain behavior of renal pelvis | |
|---|---|---|
| Billing status | Non-billable header | Non-billable header |
| Classification | C00-D49 — Neoplasms | C00-D49 — Neoplasms |
| Definition | Malignant neoplasm of renal pelvis is a non-billable ICD-10-CM category code (C65). | Neoplasm of uncertain behavior of renal pelvis is a non-billable ICD-10-CM category code (D41.1). |
| Includes | malignant neoplasm of pelviureteric junction malignant neoplasm of renal calyces | — |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources