Cysts originating from cervical lymphatic ducts are very rare affections. However, they play an important role in the differential diagnosis of supraclavicular masses. The aetiology remains unclear. Practically all cases arise from the thoracic duct; those affecting the right lymphatic duct are encountered very exceptionally.In the presented case report of a right lymphatic duct cyst, we analyzed the possible reasons for the diametrically differing incidence of cysts arising from the thoracic duct and those related to the right lymphatic duct.The cysts manifest themselves clinically as an otherwise asymptomatic supraclavicular swelling. The diagnosis is based on imaging. High T-lymphocytes and triglyceride levels in an aspirate are pathognomonic. There is no uniform opinion on the therapy. The majority of authors recommend surgical removal. Lymphatic vessels entering the cyst must be intraoperatively ligated to prevent lymph leakage.