Intravenous leiomyomatosis with cardiac extension is a rare entity. The case of a 49-year-old patient is described: she was operated on for intracaval intra-atrial leiomyomatosis. After an incomplete procedure (the tumour appeared not totally resectable), the patient was treated for a period of three years with a GnRH-analogue, whereafter the patient was doing clinically well and the tumour, although it regained some growth, was in a stable situation. This new strategy seems of certain importance to the surgeon, as it carries an alternative to a high-risk reoperation. To our knowledge, this is the first description of such a combined therapeutical approach.