Complex lymphatic anomalies (CLA) are congenital diseases of the lymphatic circulation system that are associated with significant morbidity and early mortality. While guidelines for the comprehensive evaluation of the CLA were recently published, the diagnostic approach and medical management are not standardized. This article presents the clinical features of four CLA: Gorham–Stout disease, generalized lymphatic anomaly, kaposiform lymphangiomatosis, and central collecting lymphatic anomaly. We also offer three cases from the authors’ practice and our views on diagnostic testing and disease management including supportive care, medical therapies, and other interventions.