Lymphangiomatosis is characterized by the presence of multifocal lymphangiomas that may involve the lungs, bone, liver, spleen, and mediastinum. It is part of several disorders of the lymphatic system that include lymphangiomas, lymphangiectasis, lymphangioleiomyomatosis, and other lymphatic dysplasia syndromes. The nomenclature used to classify lymphatic disorders is inconsistent and confusing, particularly when the disease involves the lungs. Consequently, simplified classification systems, such as the modified Hillard classification, divide lymphangiomatosis into single- or multiple-organ system involvement. This disease involves multiple organs in 75% of the cases.