CT evaluation of spontaneously ruptured renal angiomyolipomas with massive hemorrhage spreading into multi-retroperitoneal fascia and fascial spaces

BACKGROUND: Renal angiomyolipomas (RAMLs) can spontaneously rupture and induce hemorrhage that is usually confined to the perirenal space (PS) but may spread beyond the PS into other retroperitoneal fascia and fascial spaces, including up to the subdiaphramatic and down to pelvic extra-peritoneal regions. PURPOSE: To evaluate the computed tomography (CT) manifestations of renal angiomyolipoma (RAML) associated with spontaneous rupture and massive hemorrhage spreading beyond the PS into other retroperitoneal fascia and fascial spaces, including up to the subdiaphramatic and down to pelvic extra-peritoneal regions. MATERIAL AND METHODS: The CT scans of seven patients with spontaneously ruptured of RAMLs and massive hemorrhage (surgically and pathologically confirmed) were retrospectively reviewed. We evaluated the CT signs of the RAML itself and the regions with extensive retroperitoneal spreading after RAML rupture. RESULTS: The CT manifestations of seven cases with RAML spontaneous rupture and massive hemorrhage included the following: (a) RAML signs: size (>4.0 cm, five patients; <4.0 cm, two patients), location (periphery, six patients; central portion, one patient), component (fat tissue included, seven patients), and boundary (poorly revealed, seven patients); and (b) signs of extensive retroperitoneal spreading after RAML rupture: involving the PS and extending beyond the PS (seven patients); spread to the pelvic extraperitoneal space (seven patients); attached to the subdiaphragmatic extraperitoneal region (four patients); and extended to the contralateral retroperitoneal spaces (six patients). CONCLUSION: CT scans clearly depict both the primary tumor and complicated signs of a spontaneously ruptured RAML with massive hemorrhage, which can affect other fascial planes and retroperitoneal spaces and can extend upward to the subdiaphragmatic region and downward to the pelvic extraperitoneal region or communicate with the contralateral side.