ICD-10 Code D49.1 – Neoplasm of unspecified behavior of respiratory system (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D49.1 – Neoplasm of unspecified behavior of respiratory system
What it is
D49.1 identifies a respiratory-system neoplasm whose behavior is not clearly documented as benign, malignant, or in situ. Use it when the record confirms a tumor in the respiratory tract but does not define its biologic behavior.
Clinical signs
Clinical features vary; refer to documentation. Patients may have nonspecific respiratory findings such as cough, dyspnea, hemoptysis, or an imaging-detected mass, but the code depends on documented tumor behavior, not symptoms alone.
When to use this code
Use D49.1 when the provider documents an unspecified-behavior neoplasm involving the respiratory system, such as the trachea, bronchi, or lung, and no definitive pathology is available. It also fits when the chart notes a mass or neoplasm but does not state whether it is benign or malignant. Check documentation if the site or behavior is unclear.
Do not use for
Do not use this code for clearly benign, malignant, or in situ respiratory tumors. If the pathology or assessment specifies a different behavior code, report that code instead.
Coding tip
Confirm both anatomic site and tumor behavior in the record before assigning D49.1.