Lymphangioma, any site

Lymphangioma is a benign growth made up of abnormal lymphatic vessels that can occur anywhere in the body, most commonly in the neck and armpits. These fluid-filled masses are usually present from birth or develop in early childhood and appear as soft, compressible swellings under the skin. While typically harmless, larger lymphangiomas may require surgical removal if they cause discomfort or cosmetic concerns.