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C34.9 vs D38.1

C34.9 (Malignant neoplasm of unspecified part of bronchus or lung) compared with D38.1 (Neoplasm of uncertain behavior of trachea, bronchus and lung), from the official CMS tabular data. C34.9 and D38.1 name the same anatomical site (bronchiogenic) with a different neoplasm behavior. MedCoder-derived

Relationship

Informational

Neoplasm table relationship

C34.9
Malignant neoplasm of unspecified part of bronchus or lung
↔
D38.1
Neoplasm of uncertain behavior of trachea, bronchus and lung

Same anatomical site, different neoplasm behavior.

Same site — uncertain behavior (bronchiogenic)

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. C34.9 and D38.1 name the same anatomical site (bronchiogenic) 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

C34.9Malignant neoplasm of unspecified part of bronchus or lungD38.1Neoplasm of uncertain behavior of trachea, bronchus and lung
Billing statusNon-billable header

Report instead: C34.90, C34.91, C34.92

Billable
ClassificationC00-D49 — Neoplasms (C00-D49)C00-D49 — Neoplasms (C00-D49)
DefinitionMalignant neoplasm of unspecified part of bronchus or lung is a non-billable ICD-10-CM category code (C34.9).Neoplasm of uncertain behavior of trachea, bronchus and lung is a billable ICD-10-CM diagnosis code (D38.1).
Includes
malignant neoplasm of middle ear
—
Use additional code
code to identify:
exposure to environmental tobacco smoke (Z77.22)
exposure to tobacco smoke in the perinatal period (P96.81)
—
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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