C16.8 (Malignant neoplasm of overlapping sites of stomach) compared with C78.89 (Secondary malignant neoplasm of other digestive organs), from the official CMS tabular data. C16.8 and C78.89 name the same anatomical site (stomach) with a different neoplasm behavior.
Same anatomical site, different neoplasm behavior.
Same site — primary malignancy (stomach)
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. C78.89 and C16.8 name the same anatomical site (stomach) with a different neoplasm behavior.
From the CMS 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.
| C16.8Malignant neoplasm of overlapping sites of stomach | C78.89Secondary malignant neoplasm of other digestive organs | |
|---|---|---|
| Billing status | Billable | Billable |
| Classification | C00-D49 — Neoplasms (C00-D49) | C00-D49 — Neoplasms (C00-D49) |
| Definition | Malignant neoplasm of overlapping sites of stomach is a billable ICD-10-CM diagnosis code (C16.8). | Secondary malignant neoplasm of other digestive organs is a billable ICD-10-CM diagnosis code (C78.89). |
| Use additional code | code to identify: alcohol abuse and dependence (F10.-) | — |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources