D18.1 vs D21
D18.1 and D21 can never be reported together. ICD-10-CM declares them mutually exclusive with an Excludes1 note, meaning the two conditions cannot occur in the same patient — so exactly one of them is correct for any given encounter.
The official note, declared on D21
lymphangioma (D18.1)
D18.1
Lymphangioma, any site
Billable
- Chapter 2
- Neoplasms
- Section
- D10-D36
Indexed under
- Hemolymphangioma
- Hygroma (congenital) (cystic)
- Lymphangioendothelioma
- Lymphangioma
- Lymphangiomyoma
D21
Other benign neoplasms of connective and other soft tissue
Not billable
- Chapter 2
- Neoplasms
- Section
- D10-D36
Use when the record says
- benign neoplasm of blood vessel
- benign neoplasm of bursa
- benign neoplasm of cartilage
- benign neoplasm of fascia
- benign neoplasm of fat
- benign neoplasm of ligament, except uterine
- benign neoplasm of lymphatic channel
- benign neoplasm of muscle
Excludes1 is not always absolute: where two conditions covered by the note are genuinely unrelated, CMS guidance permits reporting both. Document the reasoning rather than assuming it. More on Excludes1 vs Excludes2 · FY2027