Lymphangioma is a benign tumor that arises from the lymphatic system, which is part of the body's immune system. It typically appears as a soft, painless swelling and can occur anywhere in the body, but is most commonly found in the head, neck, and axillary regions. These tumors are often present at birth or develop in early childhood. The exact cause of lymphangioma is not well understood, but it is believed to result from malformations in the lymphatic vessels. Treatment options may include observation, surgical removal, or sclerotherapy, depending on the size and location of the tumor. While lymphangiomas are generally not harmful, they can cause complications if they compress surrounding structures.