Unexpectedly Resolved Multiple Mobile Thrombi in a Normal Thoracic Aorta Associated With Colorectal Cancer and Protein C Deficiency

Abstract

Staging System sixth edition. The patient did not have peritoneal or liver metastases. Based on the clinical presentation, TEE, and histopathology findings, the masses in the thoracic aorta were considered to be thrombi and thought to be the causative factor for the rectal perforation. Postoperative hematologic testing revealed protein C deficiency: Initial activity value, 32% (normal value, 64%-146%), and initial antigen value, 33% (normal value, 70%-150%). The patient did not have a medical history of protein C deficiency. Factor VIII, homocysteine and protein S activity, and antigen levels were within normal ranges. Anticardiolipin antibody, antinuclear antibody, proteinase-3-antineutrophilic cytoplasmic antibody, myeloperoxidase-antineutrophilic cytoplasmic antibody, and lupus anticoagulant assays all were negative. The patient did not undergo any additional surgery for the aortic thrombi, such as thrombectomy or segmental aortic resection, because it was thought to be too invasive for a patient with advanced cancer. The authors did not perform anticoagulant or thrombolytic therapy because of the significant risk of additional distal embolization. Only oral aspirin was given for aortic thrombus prophylaxis. The patient also received intensive treatment for peritonitis, including antibiotics, fluid management, and mechanical ventilation, after the surgery in the intensive care unit. His clinical course was good, and the aortic thrombi had disappeared completely on a followup CT scan performed on the 49th day of hospitalization (Fig 1B). Cyanosis of the bilateral digits, which was thought to be a sign of acute pedal arterial embolism, appeared during the clinical course, but it improved with intravenous alprostadil monotherapy. The patient was discharged to his home on the 61st day of hospitalization without any other serious distal embolism.