C79.89 vs D21.1

C79.89 (Secondary malignant neoplasm of other specified sites) compared with D21.1 (Benign neoplasm of connective and other soft tissue of upper limb, including shoulder), from the official CMS tabular data. C79.89 and D21.1 name the same anatomical site (aponeurosis) with a different neoplasm behavior.

Relationship

Informational

Neoplasm table relationship

C79.89

Secondary malignant neoplasm of other specified sites

↔

D21.1

Benign neoplasm of connective and other soft tissue of upper limb, including shoulder

Same anatomical site, different neoplasm behavior.

Same site — benign neoplasm (aponeurosis)

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. C79.89 and D21.1 name the same anatomical site (aponeurosis) 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

	C79.89Secondary malignant neoplasm of other specified sites	D21.1Benign neoplasm of connective and other soft tissue of upper limb, including shoulder
Billing status	Billable	Non-billable header Report instead: D21.10, D21.11, D21.12
Classification	C00-D49 — Neoplasms (C00-D49)	C00-D49 — Neoplasms (C00-D49)
Definition	Secondary malignant neoplasm of other specified sites is a billable ICD-10-CM diagnosis code (C79.89).	Benign neoplasm of connective and other soft tissue of upper limb, including shoulder is a non-billable ICD-10-CM category code (D21.1).
Includes	—	benign neoplasm of blood vessel benign neoplasm of bursa benign neoplasm of cartilage benign neoplasm of fascia

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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