eP275 - Synchronous Sigmoid and Rectal Adenocarcinoma with Infrarenal Aortic and Bilateral Common Iliac Artery Aneurysms

Purpose/Background: Synchronous colorectal cancers (SCRC) are defined as more than one primary colorectal cancer (CRC) identified in a patient at the time of presentation, or within six months of initial diagnosis, with a prevalence of 1% to 8%. On the other hand, solitary colorectal cancers, diagnosed with an incidental co-existing abdominal aortic aneurysm (AAA) is rare with an incidence of only 0.5 to 2%. We present the clinical management challenge of a case of synchronous sigmoid and rectal adenocarcinoma with infrarenal AAA and bilateral common iliac aneurysms.Methods/Interventions: An elderly hypertensive male presented with a month history of hematochezia and constipation. Colonoscopy showed synchronous sigmoid and rectal masses, both adenocarcinoma on histopathology. On CT scans, there was no evidence of distant metastasis, however, three aneurysms were incidentally identified at the infrarenal aorta and bilateral common iliac arteries. A dedicated CT aortogram was done that detailed the aneurysms mentioned with note of eccentric thrombus formations within the aneurysms. CEA was elevated at 17.04 ng/mL. The patient underwent a trephine proximal transverse loop colostomy for obstruction and was transferred to our institution for further management.
The patient was received with active hematochezia requiring blood transfusion. A coronary angiography was performed that showed severe 2-vessel coronary artery disease (CAD) with 90% and complete stenosis of the left anterior descending and right coronary arteries, respectively. After discussion within a multidisciplinary team, the patient underwent an extended Hartmann’s procedure with bilateral internal iliac artery ligation and was scheduled for elective endovascular aneurysm repair (EVAR). On the third postoperative day, after undergoing echocardiography with doppler studies of bilateral lower extremities, the patient presented with signs and symptoms of aneurysmal rupture. An emergency EVAR with peripheral angiography and embolectomy was performed. Completion angiography showed good contrast flow into the bilateral common iliac arteries with minimal endoleak at the infrarenal aorta. After the procedure, the patient clinically improved and was discharged after 1 week.Results/Outcomes: Histopathology showed a well-differentiated adenocarcinoma of both the sigmoid and rectum with no identified lymphovascular and perineural invasion. All margins and 38 harvested lymph nodes were negative for tumor with a pathologic stage of pT2N0 and surveillance was advised.Conclusion/

Discussion: Systematic reviews on the management of SCRC and AAA showed that performing EVAR either in one, or two, staged showed minimized delays in the management of the CRC. No clear guidelines exist yet that determine the order of which the CRC and the aneurysm are to be treated. However, most reports advocate management of the aneurysms prior to surgery for the CRC.
In the case presented, the patient presented with hematochezia requiring blood transfusion. This posed a dilemma since heparinization would be required if an EVAR, or open aneurysm surgery was to be attempted. The potential for aggravating the bleeding with anticoagulation led to our decision to proceed with resection of the SCRC first.
In conclusion, SCRC with coexisting abdominal aortic and iliac aneurysms is rare. There appears to be other similar published reports. The treatment strategies vary based on the symptoms, and their severity. Collaboration among multiple specialties is vital in managing these complex cases.Figure 1.(A) Axial CT scan image showing the synchronous sigmoid (blue arrow) and rectal (red arrow) adenocarcinoma. (B) Extended Hartmann’s procedure gross specimen showing the synchronous sigmoid (blue arrow) and rectal (red arrow) adenocarcinoma. (C) Coronal CT scan image showing the following aneurysms: an infrarenal aneurysmal dilatation (red) measuring 5.0 X 6.0 x 6.2 cm; and saccular aneurysms at the bilateral common iliac arteries (yellow) measuring 7.9 x 8.0 x 9.9 cm on the right, and 5.6 x 6.2 x 7.0 cm on the left with thrombus formation. (D) Intraoperative photo showing the bilateral common iliac aneurysms after resection of the synchronous sigmoid and rectal adenocarcinoma. (E & F) Fluoroscopy images after endovascular aneurysm repair showing stent placement and good flow on angiography. (PGH, 2023)