Anastomosing hemangioma arising from the left renal vein: A case report.

BACKGROUND: Anastomosing hemangioma (AH) is a rare subtype of benign hemangioma that is most commonly found in the genitourinary tract. Due to the lack of specific clinical and radiologic manifestations, it is easily misdiagnosed preoperatively. Here, we report a case of AH arising from the left renal vein that was discovered incidentally and confirmed pathologically, and then describe its imaging characteristics from a radiologic point of view and review its clinicopathologic features and treatment.

CASE SUMMARY: A 74-year-old woman was admitted to our department for a left retroperitoneal neoplasm measuring 2.6 cm × 2.0 cm. Her laboratory data showed no significant abnormalities. A non-contrast-enhanced computed tomography (CT) scan showed a heterogeneous density in the neoplasm. Non-contrast-enhanced magnetic resonance imaging (MRI) revealed a heterogeneous hypointensity on T1-weighed images and a heterogeneous hyperintensity on T2-weighed images. On contrast-enhanced CT and MRI scans, the neoplasm presented marked septal enhancement in the arterial phase and persistent enhancement in the portal phase, and its boundary with the left renal vein was ill-defined. Based on these clinical and radiological manifestations, the neoplasm was initially considered to be a neurogenic neoplasm in the left retroperitoneum. Finally, the neoplasm was completely resected and pathologically diagnosed as AH.

CONCLUSION: AH is an uncommon benign hemangioma. Preoperative misdiagnoses are common not only because of a lack of specific clinical and radiologic manifestations but also because clinicians lack vigilance and diagnostic experience in identifying AH. AH is not exclusive to the urogenital parenchyma. We report the first case of this neoplasm in the left renal vein. Recognition of this entity in the left renal vein can be helpful in its diagnosis and distinction from other neoplasms.