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Q1: Describe the findings in fig 1?
Figure 1 (p 586) reveals a large soft tissue mass at the region of the left psoas muscle consistent with a large psoas abscess, a haematoma, or a soft tissue tumour. The aorta is calcified and shows a small aneurysm, 4 cm in diameter, with no obvious evidence of leak.
Q2: Describe the findings in fig 2?
Figure 2 (p 586) reveals a large retroperitoneal haematoma, at the site of previously diagnosed mass at the left psoas muscle, in direct communication with the aorta.
Q3: How the patient was managed and what was the diagnosis?
This is a case of chronic contained rupture of an abdominal aortic aneurysm (AAA).
The patient was transferred to the Vascular Unit where immediate laparotomy was performed. Retroperitoneal rupture of a 4 cm abdominal aortic aneurysm was found with a 2 cm tear in the left posterolateral wall, communicating with a large pseudoaneurysm extending from the aorta to the left flank. The aneurysm was repaired using a Dacron straight graft.
His postoperative recovery was stormy with the onset of multiple organ failure. He died three weeks postoperatively.
The pathology of the aortic wall showed atherosclerosis. Bacteriological cultures from the aortic wall, haematoma, and psoas muscle were negative.
The risk of AAA rupture is associated with increasing transverse diameter of the aneurysm, and it is felt that small aneurysms, less than 5 cm, have a low risk of rupture, around 0.5% per annum.1
The diagnosis of chronic contained rupture of AAA is very difficult with the absence of the symptomatic triad of severe pain, shock, and an abdominal mass. The condition has been reported to occur in 1%–3% of cases operated upon. Misdiagnosis is very common and a rare presentation has been reported simulating obstructive jaundice,2 duodenal and ureteric obstruction,3 inguinal and femoral masses,4and symptomatic inguinal hernia.5 Femoral and sciatic neuropathy has been documented in only few cases as a rare presentation of contained rupture of AAA.6-10 It may arise from compression of the nerve or from intraneural compression of a haemorrhagic dissection into the nerve sheath.
The criteria for identifying a chronic contained rupture were described by Jones et al in 1986: known AAA, previous pain that may have resolved, haemodynamic stability, computed tomography showing retroperitoneal haematoma, and pathological confirmation of organised haematoma.11
Two mechanisms leading to sealed rupture seem to exist: slow haemorrhage and high resistance of the surrounding tissues.
Chronic contained rupture of an abdominal aortic aneurysm.
Contained rupture of an aortic aneurysm should be suspected in cases of peripheral neuropathy associated with a psoas mass even if the size of the aneurysm is less than 5 cm
A soft tissue mass within the psoas muscle and renal displacement associated with an abdominal aneurysm are the most important signs of contained aortic rupture on computed tomography.