ICD-10-CM > C00-D49 > D10-D36 > D21 > D21.3 D21.3 Benign neoplasm of connective and other soft tissue of thorax Billable/Specific Copy Code Copy Description Applicable To Benign neoplasm of axillaBenign neoplasm of diaphragmBenign neoplasm of great vessels Type 1 Excludes benign neoplasm of heart (D15.1)benign neoplasm of mediastinum (D15.2)benign neoplasm of thymus (D15.0)