C76.8 vs D49.89

C76.8 (Malignant neoplasm of other specified ill-defined sites) compared with D49.89 (Neoplasm of unspecified behavior of other specified sites), from the official CMS tabular data. C76.8 and D49.89 name the same anatomical site (abdominopelvic) with a different neoplasm behavior. MedCoder-derived

Relationship

Informational

Neoplasm table relationship

C76.8

Malignant neoplasm of other specified ill-defined sites

↔

D49.89

Neoplasm of unspecified behavior of other specified sites

Same anatomical site, different neoplasm behavior.

Same site — unspecified behavior (abdominopelvic)

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. C76.8 and D49.89 name the same anatomical site (abdominopelvic) 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.

Side by side

	C76.8Malignant neoplasm of other specified ill-defined sites	D49.89Neoplasm of unspecified behavior of other specified sites
Billing status	Billable	Billable
Classification	C00-D49 — Neoplasms	C00-D49 — Neoplasms
Definition	Malignant neoplasm of other specified ill-defined sites is a billable ICD-10-CM diagnosis code (C76.8).	Neoplasm of unspecified behavior of other specified sites is a billable ICD-10-CM diagnosis code (D49.89).
Includes	Malignant neoplasm of overlapping ill-defined sites	'growth' NOS neoplasm NOS new growth NOS tumor NOS

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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