ICD-10 Code D18.1 – Lymphangioma, any site (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D18.1 – Lymphangioma, any site
What it is
D18.1 identifies a lymphangioma, a benign malformation of lymphatic vessels. It can occur in different body sites, so the code captures the condition without specifying location.
Clinical signs
Clinical features vary; refer to documentation. Common findings include a soft, compressible mass or swelling, often present from birth or early childhood, with imaging or pathology supporting the diagnosis.
When to use this code
Use D18.1 when the provider documents lymphangioma and does not assign a more specific site code. It also fits cases described as lymphangioma, cystic lymphangioma, or lymphatic malformation when coded under this category. If the record names a different vascular or cystic lesion, check documentation before assigning this code.
Do not use for
Do not use this code for malignant tumors, generalized edema, or nonspecific masses without a documented lymphangioma diagnosis. Check documentation if the lesion is better classified elsewhere.
Coding tip
Code the documented diagnosis as written, and confirm whether the record supports a specific site or a broader lymphangioma diagnosis.