Lymphangiomatosis is a well-recognized congenital benign tumour, frequently seen in infancy and childhood, characterized by the presence of multiple lymphangiomas. The lymphangiomatosis spectrum encompasses a remarkable heterogeneity in its potential presentation, including micro- and macrocystic isolated lymphatic malformations, thoracic and intraabdominal diffuse lymphangiomatosis, and osseous and soft-tissue presentations known as Gorham disease. The disease can be considered a failure of normal lymphatic development, but the etiology remains poorly understood. Treatment has been limited to surgical resection or drainage procedures because there is no accepted effective systemic therapy.