An Incidental Hypervascular Retroperitoneal Mass

Abstract

A 69-year-old white man presented to the emergency department after a tractor-ontree collision. Contrast-enhanced computed tomography demonstrated an incidental right infrarenal, retroperitoneal mass measuring 9.7 × 7.7 × 9.1 cm (Figure 1A), with dilated tortuous supply from a lumbar artery branch and retroperitoneal lymphadenopathy. He denied any history of systemic symptoms, pain, urinary symptoms, or abnormal bowel function but described 6 years of decreased appetite. Laboratory evaluation of plasma-free metanephrine levels showed a slight elevation in normetanephrine levels (1.21 nmol/L). Given the dramatic arterial enhancement and hypertrophied perivascular plexus, biopsy was not performed, and preoperative arterial embolization was deemed appropriate to minimize intraoperative blood loss.At preoperative embolization, initial aortography identified the predominant lumbar artery branch and also demonstrated supply from a branch of the internal iliac artery (Figure 1B). These branches were embolized and the mass was devascularized. Twentyfour hours following embolization, surgical exploration was performed through a periumbilical midline incision. With no evidence of distant metastasis (peritoneal or liver), the mass was resected with partial resection of the iliopsoas muscle to achieve negative margins in conjunction with aortocaval lymphadenectomy of the enlarged lymph nodes. The mass was running parallel to the right ureter, which was meticulously dissected, and the right kidney was successfully saved. There were no complications, and the postoperative course was uneventful.