Visceral aneurysms are rare, but when limited to peripancreatic aneurysms, most of those aneurysms originate from the gastroduodenal and pancreatic duodenal arteries [10]. In our case, we observe the ruptured aneurysm of TPA originating from the SMA. An aneurysm in the SMA is rare, and its etiology is unclear. One-third of SMA aneurysms are due to septic embolism [11]. Other etiologies include arteriosclerosis, polyarteritis, nodosa, pancreatitis, biliary tract disease, neurofibromatosis, and trauma [11]. In our case, the history of rheumatoid arthritis may have played a role in aneurysm formation.
The TPA generally branches from the dorsal pancreatic artery, and runs behind the pancreas [6, 7]. Therefore, aneurysm rupture at the TPA causes bleeding in the retroperitoneum. In the case of bleeding from the aneurysm at the head of the pancreas, hemorrhage may be excreted to the pancreatic duct, bile duct, or gastroduodenum, and the symptoms may resemble those of biliary-pancreatic disease [12,13,14,15]. In the case of the TPA aneurysm, it found with the onset of pancreatitis have been reported [16]. However, bleeding of the caudal pancreas, as in our case, does not cause such symptoms or an increase in pancreatic enzymes.
Our patient presented with acute back and abdominal pain, but her vital signs were first stable. Her history of a duodenal ulcer several years ago and current administration of 10 mg of steroids per day may have delayed the diagnosis of a ruptured TPA aneurysm, leading to heavy bleeding.
Abdominal contrast-enhanced CT is useful for finding extravasation. Selective angiography of abdominal artery enables us to find the site of bleeding in greater detail and treat aneurysms at the same time.
When it comes to treating TPA, it was reported that a TPA aneurysm which was successfully embolized by angiography in 1982 [16]. In this case report, there is one week between diagnosis and treatment. This patient had time to spare because the aneurysm had not ruptured. In our case, the patient went into shock in the emergency room. In addition, the branch of the SMA to the aneurysm was too thin and complex to conduct IVR. Endovascular treatment could pose a risk of covering important branches of the SMA main trunk and could make embolization of the distal branch difficult [17]. Therefore, we selected surgical hemostasis.
Surgical treatment can be performed by simple ligation in most cases, but sometimes more invasive procedures are required [18]. For a ruptured splenic aneurysm, splenectomy or distal pancreatectomy may be performed [19]. On the other hand, pancreaticoduodenectomy is performed for approximately 14% of ruptured pancreaticoduodenal aneurysms [13]. In our case, the aneurysm was only 5 mm, and simple ligation and resection of the aneurysm were sufficient to control hemorrhage.
In addition, the hematoma may not reveal the bleeding point and emergency laparotomy may endanger the patient’s life. However, if the bleeding point is known before surgery, the advantage of surgery is that it can stop bleeding directly. We pressed the pancreas itself with blocking forceps to stop the bleeding. After hemostasis, we found a TPA aneurysm and ligated it. Postoperative pancreatitis may be caused by pressure on the pancreas during the operation, but it does not have a significant impact on the postoperative course.
