A 40-year-old man walked into a hospital in Japan complaining of lower abdominal pain. A CT scan found a flat, plate-like object sitting inside his distal abdominal aorta, the main artery running down through the belly toward the legs, along with a pocket of old blood up near the tip of his heart.
The object was a cutter knife blade, roughly 10 millimeters wide and 40 millimeters long. Three months earlier, while working with a cutter knife, he had sustained a penetrating injury to his left front chest wall. He had come to Japan as a migrant worker, and language barriers and cost had kept him from seeking care at the time.
The case, written up by a surgical team including physicians at Chiba Kaihin Municipal Hospital, was reported this spring in the Journal of Vascular Surgery Cases, Innovations and Techniques. The authors describe it as intravascular migration of a sharp foreign body, and they characterize that particular journey as rare.
Lower Abdominal Pain with No Obvious Explanation
The presenting complaint was unremarkable. Lower abdominal pain sends enormous numbers of people to emergency departments every year, and the overwhelming majority have nothing to do with retained metal.
What made this case solvable was imaging that covered more than the area that hurt. The chest CT showed a localized hematoma next to the cardiac apex on the left anterior chest wall. The abdominal CT showed the foreign body. Neither finding makes much sense alone. Together they trace a path: the blood collection near the heart marks where something went in, and the blade was found a considerable distance downstream.
The authors' point about whole-body imaging in patients with atypical symptoms after penetrating trauma is the practical takeaway, and it depends on someone knowing there was trauma. In this case, nobody did until the scan forced the question.
Forty Millimeters of Steel in the Wrong Blood Vessel
Surgeons proceeded to a semi-emergent abdominal aortic replacement, an open operation in which the damaged segment of the aorta is replaced with a graft. They approached through a midline laparotomy, opened the retroperitoneum, clamped the infrarenal aorta and made a longitudinal incision in the vessel.
What they found inside was not a blade floating loose in the bloodstream. The aortic wall showed severe inflammatory thickening, extending from just below the origin of the inferior mesenteric artery down to the point where the aorta splits into the iliac arteries. The blade itself was embedded in that wall, running from the aorta below the inferior mesenteric artery to the origin of the right common iliac artery. It was carefully removed.
The inflammation is the reason the patient was alive to complain of abdominal pain. Tissue reaction around a foreign body can seal and stabilize what would otherwise be a catastrophic hole in a high-pressure vessel. It is also why the blade could sit there for months producing a vague ache rather than sudden hemorrhage.
How Sharp Objects Travel Inside the Body
Intravascular foreign bodies are a recognized, if uncommon, category. Most reported cases involve fragments of medical hardware, such as broken catheter pieces or guidewires, or needles. A sharp object entering the bloodstream through a puncture wound and then relocating is far rarer.
Retained blades after penetrating trauma, by contrast, are documented regularly. Surgeons in Tanzania reported a knife blade found in a man's right hemithorax eight years after multiple stab wounds treated with first aid alone, discovered only when he developed a discharging chest wall sinus. A South African trauma center reviewing 15 years of retained knives and blades in stab wounds counted 40 patients and found that most were hemodynamically stable on arrival, which is exactly why imaging before extraction matters. An earlier series from the same center found that simple withdrawal was possible in 58 percent of retained blades, with bleeding after extraction in only 5 percent.
Blades that reach the aorta are a different problem. Reporting a case of a retained blade with aortic injury after a stab to the mid-back, surgeons noted that most penetrating aortic injuries prove fatal before or during transport, and cited a long-term survival rate of about 30 percent among patients who reach care with signs of life. Their patient survived in part because the blade stayed put and tamponaded the wound, which is the same mechanism that kept the Japanese patient alive.
The Injury That Never Got Treated
The detail that turns this from a surgical curiosity into something with wider relevance is the occupational injury three months earlier that went untreated.
Cutter knives, the retractable snap-off utility blades used in warehouses, workshops and construction sites, break by design. A blade segment entering the chest wall may produce a wound that looks minor and closes on its own. Without imaging, there is no way to know whether a fragment stayed behind.
This is one patient, and one case report cannot establish how often blade fragments migrate or what proportion of unreported workplace punctures leave something behind. It does not support any general screening recommendation. What it does illustrate is that the window for finding a retained fragment cheaply and safely is early, and that the barriers to using that window are often practical rather than medical. Language, money and immigration status decide who gets a scan as surely as symptoms do.
The blade came out during a major aortic operation rather than during a straightforward wound exploration three months earlier. Anyone with a puncture wound from a broken blade, however small it looks, has reason to get it evaluated.
Key Questions Answered
What was found and where?
A cutter knife blade about 10 millimeters wide and 40 millimeters long, embedded in the wall of the distal abdominal aorta between the inferior mesenteric artery and the right common iliac artery.
How did it get there?
The authors describe intravascular migration following a penetrating injury to the left front chest wall three months earlier. A hematoma near the cardiac apex marked the likely entry point.
Why did it not kill him?
Severe inflammatory thickening of the aortic wall had formed around the blade, which can seal what would otherwise be an uncontrolled bleed. The report describes stabilization, not an absence of danger.
How was it treated?
Surgeons removed the blade during a semi-emergent abdominal aortic replacement, an open operation replacing the damaged segment with a graft.
Does this mean minor puncture wounds need scans?
No. This is a single case report and establishes no screening rule. It does support prompt evaluation of any puncture wound from a broken blade.
Why did it take three months to find?
He did not seek care at the time because of language barriers and cost, so no one looked. The blade was found only when imaging was ordered for unexplained abdominal pain.
