Aortic Arch Mural Thrombus Concurrent with Deep Surgical-Site Infection after Colorectal Cancer Surgery in an Enhanced Recovery after Surgery Program: A Case Report.

[INTRODUCTION] Aortic mural thrombus (AMT) in a non-atherosclerotic aorta is rare but potentially catastrophic and may be difficult to distinguish from septic aortic pathology when it occurs alongside a deep postoperative infection. Enhanced recovery after surgery (ERAS) shortens hospital stay and shifts the recognition of serious complications to the early post-discharge period. We report the case of a patient who underwent colorectal cancer surgery within an ERAS protocol who developed a large AMT on POD 10, coincident with positive deep surgical-site infection (SSI) but without bacteremia or aortitis on imaging.

[CASE PRESENTATION] A 76-year-old male with stage IVc cecal adenocarcinoma and diabetes underwent robotic-assisted ileocecal resection via the ERAS pathway. Prophylactic cefmetazole was discontinued within 24 h, and the patient was discharged on POD 5 with down-trending but elevated C-reactive protein levels. On POD 10, the patient presented with fever, leukocytosis, and decreased mobility. Contrast-enhanced CT revealed a ~38-mm AMT without mural thickening, abnormal enhancement, periaortic fat stranding, aneurysmal dilatation, or complex atherosclerotic plaque, in addition to deep port-site infection and intra-abdominal abscesses. Blood cultures (two sets) remained negative, whereas abscess and wound cultures yielded with polymicrobial co-pathogens. The patient underwent surgical washout and drainage, broad-spectrum antibiotics (piperacillin-tazobactam, followed by ceftriaxone and metronidazole), and systemic anticoagulation with unfractionated heparin. Transesophageal echocardiography showed a mural arch mass corresponding to the CT lesion, but no definite valvular vegetation or new significant regurgitation. On POD 16, the patient developed acute left common-internal carotid occlusion with a large middle cerebral artery infarction and died on POD 20 of septic shock and disseminated intravascular coagulation.

[CONCLUSIONS] In this patient who underwent ERAS colorectal cancer surgery, AMT developed around POD 10 in parallel with SAG-positive deep SSI, but without aortitis or bacteremia, favoring a bland mural thrombus driven by malignancy- and sepsis-related hypercoagulability while retaining nonbacterial thrombotic endocarditis/infective endocarditis in the differential diagnosis. The case highlights PODs 7-10 as a vulnerable window in ERAS pathways and supports a focused safety bundle that includes CRP-guided discharge thresholds, selective low-dose imaging, and POD 7 ± 1 follow-up to improve early post-discharge surveillance.