C44.90 (Unspecified malignant neoplasm of skin, unspecified) compared with C79.2 (Secondary malignant neoplasm of skin), from the official CMS tabular data. C44.90 and C79.2 name the same anatomical site (connective tissue) with a different neoplasm behavior. MedCoder-derived
Same anatomical site, different neoplasm behavior.
Same site — secondary malignancy (connective tissue)
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. C44.90 and C79.2 name the same anatomical site (connective tissue) 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.
| C44.90Unspecified malignant neoplasm of skin, unspecified | C79.2Secondary malignant neoplasm of skin | |
|---|---|---|
| Billing status | Billable | Billable |
| Classification | C00-D49 — Neoplasms | C00-D49 — Neoplasms |
| Definition | Unspecified malignant neoplasm of skin, unspecified is a billable ICD-10-CM diagnosis code (C44.90). | Secondary malignant neoplasm of skin is a billable ICD-10-CM diagnosis code (C79.2). |
| Includes | malignant neoplasm of sebaceous glands malignant neoplasm of sweat glands Malignant neoplasm of unspecified site of skin | — |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources