A Rare Case of an Abdominal Giant Mass Induced by Pancreatitis

Question: A 54-year-old man experienced intermittent abdominal pain for more than 4 months, with the physical examination finding of epigastric tenderness. He had a long history of alcohol consumption. Laboratory tests showed significantly elevated amylase (404 U/L) and lipase (1071 U/L), and the clinician highly suspected pancreatitis. To clarify the diagnosis and the severity of the patient’s condition, the patient underwent abdominal computed tomography (CT) and magnetic resonance imaging, which showed increased fat density around the pancreas, visible as multiple patchy exudative shadows (Figure A, red arrows) with blurred borders and dilated pancreatic ducts. A pseudocyst measuring approximately 3.4 cm × 2.8 cm × 2.3 cm was seen in the hooked part of the pancreas (Figure B, red arrow), and he was definitively diagnosed with pancreatitis in combination with laboratory tests and these imaging findings. More importantly, an abdominal mass measuring 7.0 cm × 5.0 cm × 4.3 cm was seen in the area above the head of the pancreas (Figure A–E, white arrow), which appeared as a hypodense shadow on CT with heterogeneous density and relatively clear borders, and the lower edge was not related to the head of the pancreas. Magnetic resonance imaging showed that the mass showed an equal-low mixed signal in T1WI, a high-low mixed signal in T2WI, and a high signal at the edge and a low signal at the center of the mass in diffusion weighted imaging. What is your diagnosis? See the Gastroenterology website (www.gastrojournal.org) for more information on submitting to Gastro Curbside Consult. The enhanced CT maximum intensity projection coronal image showed that the lesion was significantly enhanced and similar to that of the common hepatic artery, with the tumor measuring approximately 6.9 cm × 4.4 cm × 4.6 cm (Figure F, red arrow; Video 1), and the neck of the tumor was approximately 1.0 cm, with the tip of this “gourd-shaped” mass connected to the common hepatic artery through the neck (green arrow), and a curved low-density mural thrombus was seen around it (black arrow). Three-dimensional volumetric reproduction technique showed the abdominal trunk artery emanating from the splenic artery (Figure G, green arrow), the common hepatic artery (red arrow), and a localized “gourd-shaped” structure of the common hepatic artery (white arrow); CT enhancement also revealed the disappearance of the portal vein trunk (Figure H, black arrow) with cavernous transformation of the portal vein. In summary, we tentatively diagnosed a common hepatic artery aneurysm (CHA) for this abdominal mass. Finally, our diagnosis was further confirmed using digital subtraction angiography, which showed a localized “gourd-shaped” ectasia (Figure I, white arrow; Video 2) of the common hepatic artery (black arrow), which was filled inward with a contrast medium. After 2 weeks of antipancreatitis treatment including acid suppression and inhibition of pancreatic enzyme activity, the patient’s clinical symptoms were significantly relieved. Due to the large size of the “gourd-shaped” aneurysm of the common hepatic artery in this case, there is a risk of rupture and bleeding, which may endanger the patient’s life. Therefore, the interventional surgeon treated him with overlying stent placement for CHA after the patient’s pancreatitis was controlled, and the postoperative treatment was effective, with digital subtraction angiography review showing good stent deployment (Figure J) and no aneurysm visualization (Figure K). The patient has been discharged from the hospital and is being followed up regularly. Giant visceral aneurysms (>5 cm) are a rare condition, occurring even more rarely in giant arteries of the common hepatic artery, with an estimated incidence of CHA of about 0.002%.1Abbas M.A. Fowl R.J. Stone W.M. et al.Hepatic artery aneurysm: factors that predict complications.J Vasc Surg. 2003; 38: 41-45Abstract Full Text Full Text PDF PubMed Scopus (246) Google Scholar The mortality rate is high if left untreated, so early diagnosis and treatment of CHA are critical. The causative factors of visceral aneurysm include trauma, surgical injury, arterial degeneration, atherosclerosis, diabetes mellitus, smoking, and autoimmune diseases.2Chiaradia M. Novelli L. Deux J.F. et al.Ruptured visceral artery aneurysms.Diagnos Interven Imag. 2015; 96: 797-806Crossref PubMed Scopus (22) Google Scholar However, CHA caused by pancreatitis has rarely been reported previously. We consider that the mechanism of the formation of CHA in this case was due to the digestion, destruction, and erosion of the surrounding blood vessels by pancreatic protein hydrolase released from pancreatitis,3Nam H.S. Noh M.H. Han J.E. et al.Left hepatic artery pseudoaneurysm caused by acute pancreatitis. medical principles and practice.I J Kuwait University Health Science Centre. 2017; 26: 192-194Google Scholar resulting in the degeneration of the middle elastic fibers in the wall of the common hepatic artery, local thinning and destruction of the wall, and loss of its original elasticity, and the gradual formation of the aneurysm by the restricted outward expansion of the arterial wall under the impact of high-pressure blood flow. This rare but serious complication of pancreatitis should be understood and further studied by clinicians and radiologists to give advice for a healthy life and to guide treatment strategies. Surgical and endovascular interventions will help reduce the development of this serious complication and patient mortality. eyJraWQiOiI4ZjUxYWNhY2IzYjhiNjNlNzFlYmIzYWFmYTU5NmZmYyIsImFsZyI6IlJTMjU2In0.eyJzdWIiOiIxNWJkM2ExNjU5NGFlOTU2YWVkYzg3ODg5ZDU0Y2YwYSIsImtpZCI6IjhmNTFhY2FjYjNiOGI2M2U3MWViYjNhYWZhNTk2ZmZjIiwiZXhwIjoxNjkxNDUwODU0fQ.CUrgkids1Gr19hJexTgoK2pkAzm3AuZ0VSsHB6X3_5cY4B-AbzevoM_aUXUW2I4DPSVPt_2HZmleAv_Y70NOcotkoKeKLAwnPPW9Ts-qLvK9d5EXIyHXPFzAt4pUESarFc6Xvr0dUpgWpPZtRv20owJNxySu2yYW5qTtTCb3gLYheS1VPxdXJP_mPQyopq7asKIW9iIw2elnHFdoa43I4BgG1Y80SF5TVmjf0gyJrBoj7CCZK7UDuPGZxFlGa4PnSwkYjkTpi1PsTnamA2hC76PHWhAZ1i_XCGMe-hahA0nr-qC-XevwUY618CrMU_aThM0N4OnDGfxkrT882itA5g Download .mp4 (18.48 MB) Help with .mp4 files Video AEnhanced CT showed that the lesion was significantly enhanced and the degree of enhancement was similar to that of the common hepatic artery.eyJraWQiOiI4ZjUxYWNhY2IzYjhiNjNlNzFlYmIzYWFmYTU5NmZmYyIsImFsZyI6IlJTMjU2In0.eyJzdWIiOiJlOWY2MDU5YmFkZGM5MjQ3ZjJiYWEzZTQ3OWJjZjNkNSIsImtpZCI6IjhmNTFhY2FjYjNiOGI2M2U3MWViYjNhYWZhNTk2ZmZjIiwiZXhwIjoxNjkxNDUwODU0fQ.nHE-pQwyFIg1oAKLwlqr5-IigwhRXCHxfwvAGl-daNLBRUUfL6UBrXhfogO6t8k7euinQDiCchTARP0OWAQg6epV7t4ZbeRQfQaFPBaFmbxAToHGTx3n0kdoIuHX0h5vu3sh7S11DxV58EH9me132CzINjtmRXEAFUiqzmyE9POKLqqMalbnDdH6Du6-wllh9YdOX7Q6PjacFboQ2J3XoNzjsaYfIcfo4sRjFlED4coBzUQotnRnGizVoN3X4WupgqVbf4LaqYiH6-kET5oU4Nxf5UAsFZQ9uhSZgs0i7SqZW5BYzLKqQrvCT3a430VHwHhmrAbPbv80HJ47cmqdBA Download .mp4 (3.76 MB) Help with .mp4 files Video BThe digital subtraction angiography movie showed a cucurbit-shaped aneurysm originating from the common hepatic artery.