C79.49 vs D49.89

C79.49 (Secondary malignant neoplasm of other parts of nervous system) compared with D49.89 (Neoplasm of unspecified behavior of other specified sites), from the official CMS tabular data. C79.49 and D49.89 name the same anatomical site (ciliary body) with a different neoplasm behavior. MedCoder-derived

Relationship

Informational

Neoplasm table relationship

C79.49

Secondary malignant neoplasm of other parts of nervous system

↔

D49.89

Neoplasm of unspecified behavior of other specified sites

Same anatomical site, different neoplasm behavior.

Same site — unspecified behavior (ciliary body)

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. C79.49 and D49.89 name the same anatomical site (ciliary body) 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

	C79.49Secondary malignant neoplasm of other parts of nervous system	D49.89Neoplasm of unspecified behavior of other specified sites
Billing status	Billable	Billable
Classification	C00-D49 — Neoplasms	C00-D49 — Neoplasms
Definition	Secondary malignant neoplasm of other parts of nervous system is a billable ICD-10-CM diagnosis code (C79.49).	Neoplasm of unspecified behavior of other specified sites is a billable ICD-10-CM diagnosis code (D49.89).
Includes	—	'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