Clostridium septicum Aortitis with Synchronous Ascending Colon and Rectal Adenocarcinoma

Abstract

Introduction: Sepsis secondary to C. septicum is associated with underlying occult colorectal malignancy and has a high mortality. Case Report: A 66-year-old Puerto Rican male with no significant PMH presented with three days of generalized abdominal pain and one episode of bright red blood mixed with stool. He reported subjective fevers with chills and constipation for one month. He denied nausea, vomiting, diarrhea, pruritus, weight loss, fatigue or jaundice. There was no family history of colon cancer. The patient had normal vital signs except for a temperature 101 F. Lab results were significant for leukocytosis and microcytic anemia. An abdominal ultrasound was suggestive of right colon mass and infrarenal aortitis, confirmed on the CT scan. (Image-1 and 2). Colonoscopy revealed a 2 cm mass in the proximal ascending colon and a 5 cm rectal mass (Image-3), both suspicious for malignancy. As resection of both masses at the time of aortic surgery seemed too high risk and the right colon mass was the more likely infectious culprit based on review of literature, resection of the rectal mass was thus deferred. The patient underwent transabdominal excision of infected infra-renal abdominal aorta, proximal bilateral common iliac arteries and proximal inferior mesenteric artery, followed by reconstruction with aorto-iliac cryopreserved homograft. An extended right hemi-colectomy and end ileostomy were performed as well. Cultures from blood and aorta grew C. septicum, sensitive to ampicillin-sulbactam. The right colon mass was adenocarcinoma on pathology. The patient improved clinically and completed six weeks of antibiotics. Follow up PET CT scan revealed non-specific findings. Three months later, patient underwent transanal intramural excision of rectal mass. It was adenocarcinoma on histology but was negative for C. septicum. Patient had a low oncotype DX recurrence score and was offered but declined adjuvant chemotherapy.Figure 1Figure 2Figure 3Conclusion: This is the first case of C septicum aortitis in the setting of synchronous colon and rectal adenocarcinomas. Antibiotics, aortic reconstruction and curative resection of underlying occult colon cancer (source of infection) are the cornerstone in the treatment of C. septicum aortitis. Right-sided colon cancer is the more common location of the source of infection in the setting of C. septicum aortitis.