What is Lymphangioma?

General term for tumors formed by a mass of anomalous lymphatic vessels or channels that vary in size, are usually greatly dilated, and are lined with normal endothelial cells; lymphoid tissue is usually present in the peripheral portions of the lesions, which are present at birth, or shortly thereafter, and probably represent maldevelopment of lymphatic vessels (rather than true neoplasms); they occur most frequently in the neck and axilla, but may also develop in the arm, mesentery, retroperitoneum, and other sites.