The body’s envelope, consisting of skin and subcutaneous fat tissue, is equipped with a draining lymphatic system and is thus directly affected by its dysfunction. In addition to the clinical signs of lymphedema, there are various secondary diseases in this area that one should know, especially since they are easy to diagnose. A chronic lymphedema is an “immunocompromised district,” microbiologically classically documented by the tendency to recurrent erysipelas. It is apparently also characterized by a limited tumor surveillance, especially with regard to blood endothelial cell neoangiogenesis. The still prognostically unfavorable lymphedema-associated angiosarcoma (Stewart-Treves syndrome) is the classic clinical example for this. Nonvanishing hematoma-like skin lesions are alarming signs and require immediate histological clarification.