Malignant tumour arising in chronic congenital or acquired lymphedema is a rare medical condition. However it must be well known because of the usual severity of these highly malignant neoplasms. Stewart-Treves angiosarcoma is the most frequent tumour: it is a vascular malignant tumour, which mostly occur in post-surgical or radiotherapeutic lymphedema for breast cancer. It differs from secondary metastasis arising in lymphedema although the clinical and histological appearance is often very close. Other tumours can grow on this ground: Kaposi's sarcoma, squamous cell carcinoma, malignant lymphoma, melanoma. On the pathogenic point of view, many factors converge to this tumoral occurrence: lymphatic stasis and the reorganization of the conjunctival tissue that it will entail, the local immunodeficiency, and also systemic factors as a general immunodeficiency or viral potentially oncogenic infections such as papillomavirus. In practice, the prevention of lymphedema, the regular monitoring of constituted lymphedemas, the hygienic and preventive behaviours of infections are the best arrangements to avoid this tumoral occurrence.