Renal artery pseudoaneurysm following tumor biopsy: Delayed rupture shortly after commencing chemotherapy for malignant lymphoma

A woman in her 70s with a large abdominal mass was admitted to another hospital, presenting with general malaise, poor appetite, weight loss, and night sweats. Abdominal computed tomography (CT) revealed homogeneously and mildly enhancing retroperitoneal tumor extending to the renal hilum and sinus along the urinary tract, causing peripheral compression of the normal renal parenchyma. A percutaneous renal biopsy under sonographic guidance confirmed the diagnosis of diffuse large B-cell lymphoma. A follow-up CT scan performed at our hospital revealed further enlargement of the lymphoma and the presence of a postbiopsy hematoma in the posterior pararenal space; however, no renal artery pseudoaneurysm was identified at that time (12 days after the biopsy). Four days after initiating chemotherapy-corresponding to 16 days after the biopsy-the patient developed abdominal pain and gross hematuria, progressing to shock. Emergency CT revealed a hematoma within the right urinary tract and a renal artery pseudoaneurysm located in the renal sinus, coinciding with marked regression of the lymphoma. Transcatheter arterial embolization was performed, and the renal artery pseudoaneurysm was successfully embolized using microcoils.