ICD-10 Code D21.3 – Benign neoplasm of connective and other soft tissue of thorax (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D21.3 – Benign neoplasm of connective and other soft tissue of thorax
What it is
D21.3 identifies a noncancerous tumor arising from connective tissue or other soft tissues in the thorax. Use it when the record clearly states a benign soft tissue neoplasm in the chest wall or thoracic region.
Clinical signs
Findings may include a localized chest wall or thoracic mass, swelling, or discomfort. Clinical features vary; refer to documentation, imaging, and pathology when available.
When to use this code
Use D21.3 when the provider documents a benign neoplasm of connective or other soft tissue specifically in the thorax. It may also fit a biopsy-confirmed benign soft tissue tumor of the chest wall.
Check that the site is thoracic and that the lesion is benign, not malignant or unspecified. If the note only says “mass” or “lesion,” code only if the documentation supports a benign neoplasm.
Do not use for
Do not use this code for malignant tumors, metastatic disease, or lesions in other body sites. Check documentation if the record describes an unspecified soft tissue mass without a confirmed benign diagnosis.
Coding tip
Confirm both the benign nature and thoracic location before assigning D21.3.