C79.0 (Secondary malignant neoplasm of kidney and renal pelvis) compared with D49.51 (Neoplasm of unspecified behavior of kidney), from the official CMS tabular data. C79.0 and D49.51 name the same anatomical site (calyx) with a different neoplasm behavior. MedCoder-derived
Same anatomical site, different neoplasm behavior.
Same site — unspecified 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. C79.0 and D49.51 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.
| C79.0Secondary malignant neoplasm of kidney and renal pelvis | D49.51Neoplasm of unspecified behavior of kidney | |
|---|---|---|
| Billing status | Non-billable header | Non-billable header |
| Classification | C00-D49 — Neoplasms | C00-D49 — Neoplasms |
| Definition | Secondary malignant neoplasm of kidney and renal pelvis is a non-billable ICD-10-CM category code (C79.0). | Neoplasm of unspecified behavior of kidney is a non-billable ICD-10-CM category code (D49.51). |
| Includes | — | 'growth' NOS neoplasm NOS new growth NOS tumor NOS |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources