eP584 - A Case Report of a Large Pseudoaneurysm from an Aberrant Splenic Artery with Fistulization to the Colon

Purpose/Background: Splenic artery pseudoaneurysms (SAPs) are a rare entity estimated to occur in < 1% of the population, most commonly secondary to pancreatitis, abdominal trauma, or postoperative/iatrogenic causes.1,2 Contrary to true splenic artery aneurysms which are mostly asymptomatic, SAPs are usually symptomatic, often causing abdominal pain, hematochezia, melena or hematemesis.2 If left untreated, SAPs can fistulize into surrounding structures, and have up to a 37% risk of rupture and 90% risk of mortality. 3,4 The timely diagnosis and treatment of SAPs is therefore crucial in the management of these patients. We present a case of a large SAP of an aberrant splenic artery with fistulization to transverse colon in a patient presenting with rectal bleeding and hemodynamic instability.Methods/Interventions: An 89 year old female with a history of atrial fibrillation on anticoagulation, hypertension and hyperlipidemia presented with complaints of bright red blood per rectum and a 2-week history of abdominal pain, nausea, vomiting, and multiple near-syncopal episodes. After initial resuscitation for noted anemia and hypotension, a CT angiography showed an aberrant splenic artery originating directly from the lateral margin of the aorta with a mass-like, 10.7cm SAP arising from a superior pole segmental branch, abutting the pancreatic tail, with contrast extravasation into the adjacent colon. Emergent transcatheter coil embolization (TCE) was performed with successful resolution of bleeding and stabilization of hemoglobin levels. A subsequent colonoscopy showed a hemostatic fistula at the splenic flexure communicating with the retroperitoneum. A repeat CT showed a persistent 8cm, air-containing, retroperitoneal fluid collection fistulizing to the colon, suspected to be the embolized SAP sac. The fistula and SAP were resected en block with a laparoscopic splenectomy and splenic flexure colectomy with anastomosis.Results/Outcomes: Postoperatively she developed leukocytosis and a small peripancreatic fluid collection treated with percutaneous drainage and antibiotics. She also had some pulmonary complications due to pre-existing cardiac comorbidities, however, she ultimately recovered well with no further bleeding.Conclusion/

Discussion: SAPs can be fatal if untreated, but their diagnosis can be challenging, especially given the nonspecific symptoms associated with them. In some cases, addressing the risk factors for SAPs could alert clinicians to the pathology, however this patient denied any abdominal trauma, pancreatitis or other relevant history. The etiology of her SAP remains unclear, and there is no literature describing associations between aberrant arterial anatomy with SAPs, but performing the appropriate evaluations and interventions, including a CT angiogram and subsequent confirmatory arteriogram, allowed for the timely TCE of the SAP and stabilization of a patient who was in hemorrhagic shock. The management of SAPs has evolved in recent years, with endovascular approaches gaining favor over more invasive surgical interventions. TCE will often suffice for the treatment of SAPs and to prevent a likely fatal rupture, but this patient had persistent fistulization of the SAP to the splenic flexure with associated phlegmonous changes despite successful hemostasis with endovascular techniques.5 Therefore, en bloc resection of the fistula with a laparoscopic splenectomy and splenic flexure colectomy allowed for removal of the pathology and prevention of a recurrent SAP or other complication.