The term «lymphatic malformations» (LMs) refers to a wide spectrum of disorders with clinical manifestations that can vary from asymptomatic to life-threatening. LMs are most frequently found in the head and neck, accounting for up to 75 % of all cases [1]. Head and neck LMs result in airway compression, a dangerous complication requiring a tracheostomy, and significant cosmetic deformities [16]. According to a Japanese group of authors, up to 14 % of head and neck LMs can extend to the superior and anterior mediastinum, which increases the risk of airway obstruction [1, 16]. The incidence of abdominal and thoracic LMs is up to 20 % [2] 5 % and 6 % for each type [3], respectively. In some cases, they may be asymptomatic and incidentally diagnosed during a medical examination for other reasons. In 90 % of cases, LMs are diagnosed in pediatric patients by the age of 2 years due to clinical symptoms [3], some of which require urgent medical care. Other life-threatening complications of extensive vascular malformations may be associated with coagulation disorders [4].