ICD-10 Code D02.4 – Carcinoma in situ of respiratory system, unspecified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D02.4 – Carcinoma in situ of respiratory system, unspecified
What it is
D02.4 identifies carcinoma in situ in the respiratory system when the exact site is not specified. It means abnormal cells are confined to the lining layer and have not invaded deeper tissue.
Clinical signs
Clinical features vary; refer to documentation. This diagnosis is usually confirmed by pathology, with notes describing in situ malignant change in a respiratory tract site such as bronchus or trachea.
When to use this code
Use D02.4 when the provider documents carcinoma in situ of the respiratory system but does not name a more specific respiratory site. It is also appropriate when the record confirms an in situ lesion and laterality or exact location is unavailable. Code from the documented diagnosis, not from suspicion alone.
Do not use for
Do not use this code for invasive respiratory cancers, benign lesions, or dysplasia without carcinoma in situ. If the record names a specific respiratory site, check documentation for a more precise code.
Coding tip
Query for the exact respiratory site whenever possible, because “unspecified” should be used only when the documentation truly lacks detail.