C78.80 vs D13.99

C78.80 (Secondary malignant neoplasm of unspecified digestive organ) compared with D13.99 (Benign neoplasm of ill-defined sites within the digestive system), from the official CMS tabular data. C78.80 and D13.99 name the same anatomical site (alimentary canal or tract) with a different neoplasm behavior.

Relationship

Informational

Neoplasm table relationship

C78.80

Secondary malignant neoplasm of unspecified digestive organ

↔

D13.99

Benign neoplasm of ill-defined sites within the digestive system

Same anatomical site, different neoplasm behavior.

Same site — benign neoplasm (alimentary canal or tract)

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

Can these codes be reported together?

Same site, different neoplasm behavior. C78.80 and D13.99 name the same anatomical site (alimentary canal or tract) 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.

Side by side

	C78.80Secondary malignant neoplasm of unspecified digestive organ	D13.99Benign neoplasm of ill-defined sites within the digestive system
Billing status	Billable	Billable
Classification	C00-D49 — Neoplasms (C00-D49)	C00-D49 — Neoplasms (C00-D49)
Definition	Secondary malignant neoplasm of unspecified digestive organ is a billable ICD-10-CM diagnosis code (C78.80).	Benign neoplasm of ill-defined sites within the digestive system is a billable ICD-10-CM diagnosis code (D13.99).
Includes	—	Benign neoplasm of digestive system NOS Benign neoplasm of intestine NOS Benign neoplasm of spleen

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Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources