[Arterial hypertension in renin-producing retroperitoneal leiomyosarcoma].

A case report of an extrarenal retroperitoneal metastatic leiomyosarcoma with associated paraneoplastic renin production is presented. Due to the renin excess syndrome, accelerated hypertension was present combined with the signs of secondary hyperaldosteronism, hypokalemia, and alkalosis. In contrast to other publications of extrarenal malignoma with paraneoplastic renin activity, this case elucidates a histologically close relationship to epitheloid muscle cells of kidney vasa afferentia and derived benign tumors. The retroperitoneal tumor and its brain metastase were morphologically identical. In contrast to histological criteria only the primary tumor exhibited high renin activity, no activity could be detected in the metastase.