Rare disease
CASE REPORT
A pancreaticoduodenal artery aneurysm Jason Robert Lewis, Jonathan Simon Refson Department of Vascular Surgery, The Princess Alexandra Hospital, Harlow, UK Correspondence to Jason Robert Lewis, [email protected] Accepted 26 May 2015
SUMMARY A 70-year-old man was investigated with CT imaging for haematuria. An incidental finding was made of a large inferior pancreaticoduodenal artery aneurysm. Following a period of monitoring, the patient underwent open repair of the aneurysm. This case report highlights an unusual pathology and discusses the clinical complexities related to its management.
colorectal team reviewed the patient and his images were discussed in a multidisciplinary team (MDT) meeting. A decision was made to perform a right hemicolectomy to remove the 10 cm×7 cm×6 cm lesion from the caecum. The specimen was sent for histological evaluation and later confirmed a mucinous cystadenoma of the appendix.
INVESTIGATIONS BACKGROUND Aneurysms involving the pancreaticoduodenal artery are unusual, accounting for fewer than 2% of all visceral aneurysms.1 Approximately 100 cases have been reported in the literature to date, ranging from 0.7 to 1.2 cm (median 0.9 cm) in anteroposterior (AP) diameter.2 3 Both true and false aneurysms have been reported. This case highlights an unusual pathology and the complexity of its management. We consider the multimodal aetiology of visceral aneurysm formation and consider the management options.
CASE PRESENTATION A 70-year-old Caucasian man presented with a history of haematuria. A diagnosis of renal calculi was suspected and he was investigated with CT of the kidney, ureter and bladder. The images failed to identify a renal calculus but revealed two incidental pathologies. The first was an infiltrating lesion in the posterior wall of the caecum (figure 1). The second was a 3 cm visceral aneurysm located between the uncinate process of the pancreas and the superior mesenteric artery (SMA). The aneurysm arose from the inferior pancreaticoduodenal artery. While the patient was not a know arteriopath, a first-degree relative had died some years previously of a ruptured splenic aneurysm. The
To cite: Lewis JR, Refson JS. BMJ Case Rep Published online: [please include Day Month Year] doi:10.1136/bcr-2014207408
Figure 1 CT of the kidney, ureter and bladder. A mass measuring 10 cm×7 cm×6 cm can be seen emerging from the caecum in the right iliac fossa (indicated by arrow).
Following the procedure, CT angiography was performed. The images were discussed in a vascular MDT meeting (figure 2) and a consensus sought from two consultant vascular surgeons, two base hospital interventional radiologists and an external interventional radiologist. The decision was made to assess for morphological change by performing six monthly CT angiography.
DIFFERENTIAL DIAGNOSIS True inferior pancreaticoduodenal artery aneurysm While a stenosis of the coeliac trunk could not be demonstrated, the degree of stenotic change within the coeliac artery changed on angiography with expiration and inspiration. However, dilated arteries could be seen adjacent to the aneurysm, suggesting increased blood flow in the pancreaticoduodenal arcade. The calcification of the aneurysmal wall was also indicative of high-pressure blood flow, in keeping with a true aneurysm.
False inferior pancreaticoduodenal artery aneurysm Calcification within the pancreas raised the suspicion of pseudoaneurysm formation secondary to chronic pancreatitis. However, the patient did not report a previous diagnosis of pancreatitis or a chronic history of abdominal pain.
Figure 2 CT angiogram demonstrating a non-aneurysmal aorta and a 3.0 cm visceral artery aneurysm emerging from the uncinate process of the pancreas (indicated by arrow).
Lewis JR, et al. BMJ Case Rep 2015. doi:10.1136/bcr-2014-207408
1
Rare disease TREATMENT Preoperative treatment strategy The decision was made to actively monitor the patient and perform repeat angiography at six monthly intervals to assess for morphological change. An opinion was sought from an interventional radiologist to assess suitability for vessel embolisation. However, due to the size and morphology of the aneurysm, it was considered to be unsuitable for an interventional procedure. Six months following presentation, no significant change was demonstrated. Curvilinear mural calcification was noted, and the tissue planes adjacent to the artery were preserved. Further CT angiography at six monthly intervals was recommended. This again failed to demonstrate morphological change (figure 3).
Operative treatment strategy Twelve months following a right hemicolectomy, the patient developed a painful and unsightly incisional hernia (figure 4). Following consultation and consideration of the risks of surgery, it was decided to repair both the incisional hernia and the inferior pancreaticoduodenal artery aneurysm as a combined procedure. The patient presented electively for surgery in March 2014. An extended upper-midline incision was made in the abdomen and the duodenum mobilised to the right, exposing the root of the small bowel mesentery. The SMA was readily palpable within the mesentery, which permitted careful dissection to reveal the aneurysm. Several innominate feeding vessels were identified, one arising directly from the SMA. The smaller vessels were ligated using 2/0 Vicryl and LigaClips, while the larger vessel arising directly from the SMA was ligated using 2/0 Vicryl and then transfixed using 4/0 Prolene. The aneurysmal sac was excised. The total operative blood loss was 250 mL. The superior mesenteric vein and artery were both visualised and preserved, and a strong pulse was palpable beyond the ligated vessels. The rectus hernia was repaired using 1/0 nylon and the skin closed. The patient was transferred directly to the ward from the recovery room. He remained an in-patient for a total of 6 days and made an uncomplicated postoperative recovery.
OUTCOME AND FOLLOW-UP The patient was reviewed in the outpatient clinic in August 2014. Unfortunately, the patient’s recovery was prolonged by a superficial wound infection, which responded to oral antibiotics.
Figure 4 A six monthly CT angiogram failed to demonstrate aneurysmal change, but demonstrates a right-sided incisional hernia following a right hemicolectomy (indicated by arrow). Furthermore, 4 months following the procedure, a second large incisional hernia had formed and required corrective surgery.
DISCUSSION Aneurysms of the pancreaticoduodenal artery are unusual and susceptible to rupture. They can be subdivided into two types, true and false aneurysms. The vessels involved are commonly the splenic artery (60%), intestinal branches (3%), the pancreaticoduodenal artery (2%), gastroduodenal artery (1.5%) and inferior mesenteric artery (rare).4 5 Their presentation is highly varied, but the widespread use of medical imaging leads to many cases being discovered incidentally.
Cause There are numerous aetiologies for aneurysm formation. True pancreaticoduodenal artery aneurysms are associated with coeliac artery stenosis in 68–74% of cases. This causes increased blood flow in the peri-pancreatic arterial network leading to vasculature dilation.3 False aneurysms are commonly associated with acute or chronic pancreatitis. They are formed by enzymatic digestion or mechanical erosion of the vessel wall.3 6 Haemorrhage secondary to pseudoaneurysm rupture is a rapidly fatal complication of chronic pancreatitis, with mortality rates ranging from 12% to 50%.6 Genetic comorbidities implicated in aneurysm formation include connective tissue disorders such as fibromuscular dysplasia, Ehlers-Danlos and Marfan syndromes. Vasculopathies such as polyarteritis nodosa and Wegner’s granulomatosis have also been implicated.4 Of interest is the family history of a first-degree relative with a splenic artery aneurysm. This may suggest a connective tissue disorder that predisposes to aneurysmal formation. Furthermore, the patient has demonstrated a tendency to develop incisional hernias following surgery, a complication associated with connective tissue disease caused by dysregulation of collagen metabolism.7
Investigation and treatment strategies Preoperative planning
Figure 3 A six monthly CT angiogram failed to demonstrate morphological change and the aneurysm continues to measure 3.0 cm in anteroposterior diameter. 2
An aneurysm of AP diameter >2 cm should be considered for treatment; however, there is no scientific data correlating risk of rupture to aneurysm size.3 4 Both open and endovascular treatments have been reported, though several factors such as patient age, diameter of the weakened artery, presence of calcification, risks of embolisation and anatomical location of the vessel (which may lead to difficult access) should be considered when planning the operative approach.4 Lewis JR, et al. BMJ Case Rep 2015. doi:10.1136/bcr-2014-207408
Rare disease Evaluation of the haemodynamics of the pancreaticoduodenal arcade Contrast-enhanced CT scan and ultrasonography may be utilised to evaluate the vasculature of the pancreaticoduodenal arcade and facilitate management.8 CT angiography remains the ‘goldstandard’, as it permits evaluation of the vascular anatomy, which may identify the nature of aneurysm formation. Coeliac artery stenosis caused by atherosclerotic plaque formation or compression by the median arcuate ligament may increase blood flow within the pancreaticoduodenal arcade.9 The superior and inferior pancreaticoduodenal arteries arise from the gastroduodenal artery (an indirect branch of the coeliac trunk), and the SMA, respectively. The vessels form a rich network around the body of the pancreas creating a collateral blood supply between the coeliac artery and the SMA.9 Subsequently, aneurysms may occur in any of these vessels in the presence of coeliac artery stenosis.9 Increased blood flow and hypertension within the vascular network may weaken the vessel wall leading to the formation of tortuous vessels visible on CT scan.9
the decision remains difficult, and the patient should be fully counselled as to the risks and benefits of treatment.
Learning points ▸ Aneurysms involving the pancreaticoduodenal artery are unusual and complex to manage. This case highlights the multifactorial nature of their aetiology. ▸ The majority of visceral artery aneurysms are detected incidentally. This case emphasises that the examining physician should be alert to unexpected pathology, particularly when reviewing radiographs. ▸ Rupture of visceral artery aneurysms is associated with high mortality (
CASE REPORT
A pancreaticoduodenal artery aneurysm Jason Robert Lewis, Jonathan Simon Refson Department of Vascular Surgery, The Princess Alexandra Hospital, Harlow, UK Correspondence to Jason Robert Lewis, [email protected] Accepted 26 May 2015
SUMMARY A 70-year-old man was investigated with CT imaging for haematuria. An incidental finding was made of a large inferior pancreaticoduodenal artery aneurysm. Following a period of monitoring, the patient underwent open repair of the aneurysm. This case report highlights an unusual pathology and discusses the clinical complexities related to its management.
colorectal team reviewed the patient and his images were discussed in a multidisciplinary team (MDT) meeting. A decision was made to perform a right hemicolectomy to remove the 10 cm×7 cm×6 cm lesion from the caecum. The specimen was sent for histological evaluation and later confirmed a mucinous cystadenoma of the appendix.
INVESTIGATIONS BACKGROUND Aneurysms involving the pancreaticoduodenal artery are unusual, accounting for fewer than 2% of all visceral aneurysms.1 Approximately 100 cases have been reported in the literature to date, ranging from 0.7 to 1.2 cm (median 0.9 cm) in anteroposterior (AP) diameter.2 3 Both true and false aneurysms have been reported. This case highlights an unusual pathology and the complexity of its management. We consider the multimodal aetiology of visceral aneurysm formation and consider the management options.
CASE PRESENTATION A 70-year-old Caucasian man presented with a history of haematuria. A diagnosis of renal calculi was suspected and he was investigated with CT of the kidney, ureter and bladder. The images failed to identify a renal calculus but revealed two incidental pathologies. The first was an infiltrating lesion in the posterior wall of the caecum (figure 1). The second was a 3 cm visceral aneurysm located between the uncinate process of the pancreas and the superior mesenteric artery (SMA). The aneurysm arose from the inferior pancreaticoduodenal artery. While the patient was not a know arteriopath, a first-degree relative had died some years previously of a ruptured splenic aneurysm. The
To cite: Lewis JR, Refson JS. BMJ Case Rep Published online: [please include Day Month Year] doi:10.1136/bcr-2014207408
Figure 1 CT of the kidney, ureter and bladder. A mass measuring 10 cm×7 cm×6 cm can be seen emerging from the caecum in the right iliac fossa (indicated by arrow).
Following the procedure, CT angiography was performed. The images were discussed in a vascular MDT meeting (figure 2) and a consensus sought from two consultant vascular surgeons, two base hospital interventional radiologists and an external interventional radiologist. The decision was made to assess for morphological change by performing six monthly CT angiography.
DIFFERENTIAL DIAGNOSIS True inferior pancreaticoduodenal artery aneurysm While a stenosis of the coeliac trunk could not be demonstrated, the degree of stenotic change within the coeliac artery changed on angiography with expiration and inspiration. However, dilated arteries could be seen adjacent to the aneurysm, suggesting increased blood flow in the pancreaticoduodenal arcade. The calcification of the aneurysmal wall was also indicative of high-pressure blood flow, in keeping with a true aneurysm.
False inferior pancreaticoduodenal artery aneurysm Calcification within the pancreas raised the suspicion of pseudoaneurysm formation secondary to chronic pancreatitis. However, the patient did not report a previous diagnosis of pancreatitis or a chronic history of abdominal pain.
Figure 2 CT angiogram demonstrating a non-aneurysmal aorta and a 3.0 cm visceral artery aneurysm emerging from the uncinate process of the pancreas (indicated by arrow).
Lewis JR, et al. BMJ Case Rep 2015. doi:10.1136/bcr-2014-207408
1
Rare disease TREATMENT Preoperative treatment strategy The decision was made to actively monitor the patient and perform repeat angiography at six monthly intervals to assess for morphological change. An opinion was sought from an interventional radiologist to assess suitability for vessel embolisation. However, due to the size and morphology of the aneurysm, it was considered to be unsuitable for an interventional procedure. Six months following presentation, no significant change was demonstrated. Curvilinear mural calcification was noted, and the tissue planes adjacent to the artery were preserved. Further CT angiography at six monthly intervals was recommended. This again failed to demonstrate morphological change (figure 3).
Operative treatment strategy Twelve months following a right hemicolectomy, the patient developed a painful and unsightly incisional hernia (figure 4). Following consultation and consideration of the risks of surgery, it was decided to repair both the incisional hernia and the inferior pancreaticoduodenal artery aneurysm as a combined procedure. The patient presented electively for surgery in March 2014. An extended upper-midline incision was made in the abdomen and the duodenum mobilised to the right, exposing the root of the small bowel mesentery. The SMA was readily palpable within the mesentery, which permitted careful dissection to reveal the aneurysm. Several innominate feeding vessels were identified, one arising directly from the SMA. The smaller vessels were ligated using 2/0 Vicryl and LigaClips, while the larger vessel arising directly from the SMA was ligated using 2/0 Vicryl and then transfixed using 4/0 Prolene. The aneurysmal sac was excised. The total operative blood loss was 250 mL. The superior mesenteric vein and artery were both visualised and preserved, and a strong pulse was palpable beyond the ligated vessels. The rectus hernia was repaired using 1/0 nylon and the skin closed. The patient was transferred directly to the ward from the recovery room. He remained an in-patient for a total of 6 days and made an uncomplicated postoperative recovery.
OUTCOME AND FOLLOW-UP The patient was reviewed in the outpatient clinic in August 2014. Unfortunately, the patient’s recovery was prolonged by a superficial wound infection, which responded to oral antibiotics.
Figure 4 A six monthly CT angiogram failed to demonstrate aneurysmal change, but demonstrates a right-sided incisional hernia following a right hemicolectomy (indicated by arrow). Furthermore, 4 months following the procedure, a second large incisional hernia had formed and required corrective surgery.
DISCUSSION Aneurysms of the pancreaticoduodenal artery are unusual and susceptible to rupture. They can be subdivided into two types, true and false aneurysms. The vessels involved are commonly the splenic artery (60%), intestinal branches (3%), the pancreaticoduodenal artery (2%), gastroduodenal artery (1.5%) and inferior mesenteric artery (rare).4 5 Their presentation is highly varied, but the widespread use of medical imaging leads to many cases being discovered incidentally.
Cause There are numerous aetiologies for aneurysm formation. True pancreaticoduodenal artery aneurysms are associated with coeliac artery stenosis in 68–74% of cases. This causes increased blood flow in the peri-pancreatic arterial network leading to vasculature dilation.3 False aneurysms are commonly associated with acute or chronic pancreatitis. They are formed by enzymatic digestion or mechanical erosion of the vessel wall.3 6 Haemorrhage secondary to pseudoaneurysm rupture is a rapidly fatal complication of chronic pancreatitis, with mortality rates ranging from 12% to 50%.6 Genetic comorbidities implicated in aneurysm formation include connective tissue disorders such as fibromuscular dysplasia, Ehlers-Danlos and Marfan syndromes. Vasculopathies such as polyarteritis nodosa and Wegner’s granulomatosis have also been implicated.4 Of interest is the family history of a first-degree relative with a splenic artery aneurysm. This may suggest a connective tissue disorder that predisposes to aneurysmal formation. Furthermore, the patient has demonstrated a tendency to develop incisional hernias following surgery, a complication associated with connective tissue disease caused by dysregulation of collagen metabolism.7
Investigation and treatment strategies Preoperative planning
Figure 3 A six monthly CT angiogram failed to demonstrate morphological change and the aneurysm continues to measure 3.0 cm in anteroposterior diameter. 2
An aneurysm of AP diameter >2 cm should be considered for treatment; however, there is no scientific data correlating risk of rupture to aneurysm size.3 4 Both open and endovascular treatments have been reported, though several factors such as patient age, diameter of the weakened artery, presence of calcification, risks of embolisation and anatomical location of the vessel (which may lead to difficult access) should be considered when planning the operative approach.4 Lewis JR, et al. BMJ Case Rep 2015. doi:10.1136/bcr-2014-207408
Rare disease Evaluation of the haemodynamics of the pancreaticoduodenal arcade Contrast-enhanced CT scan and ultrasonography may be utilised to evaluate the vasculature of the pancreaticoduodenal arcade and facilitate management.8 CT angiography remains the ‘goldstandard’, as it permits evaluation of the vascular anatomy, which may identify the nature of aneurysm formation. Coeliac artery stenosis caused by atherosclerotic plaque formation or compression by the median arcuate ligament may increase blood flow within the pancreaticoduodenal arcade.9 The superior and inferior pancreaticoduodenal arteries arise from the gastroduodenal artery (an indirect branch of the coeliac trunk), and the SMA, respectively. The vessels form a rich network around the body of the pancreas creating a collateral blood supply between the coeliac artery and the SMA.9 Subsequently, aneurysms may occur in any of these vessels in the presence of coeliac artery stenosis.9 Increased blood flow and hypertension within the vascular network may weaken the vessel wall leading to the formation of tortuous vessels visible on CT scan.9
the decision remains difficult, and the patient should be fully counselled as to the risks and benefits of treatment.
Learning points ▸ Aneurysms involving the pancreaticoduodenal artery are unusual and complex to manage. This case highlights the multifactorial nature of their aetiology. ▸ The majority of visceral artery aneurysms are detected incidentally. This case emphasises that the examining physician should be alert to unexpected pathology, particularly when reviewing radiographs. ▸ Rupture of visceral artery aneurysms is associated with high mortality (
