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Keywords
Splenic artery aneurysm, EUS, pancreatic
mass
Introduction
A 44-year-old male was referred for EUS
evaluation of pancreatic mass.
Methods for EUS Capture
EUS examination was performed with the Pentax
FG-32UA linear array echoendoscope at 5 MHz. Images were obtained
using a Sony thermal printer and subsequently scanned and
saved in .jpg format.
Case/Body
A 44-year-old male presented to an emergency
room with a severe attack of epigastric pain associated with
nausea and vomiting. He also gave a history of recurrent,
episodic upper abdominal pain over the past ten years, occurring
about twice a year. He had undergone an upper endoscopy in
the past as work up for this abdominal pain, which was reportedly
negative.
Past medical history was negative except
for distant appendectomy and tonsillectomy. He was on no medications.
Family history was non-contributory. He was a non-smoker and
drank alcohol only occasionally.
Physical examination was unremarkable. The
abdomen was non-tender and there was no bruit, palpable mass,
or organomegaly.
Laboratory studies revealed a slightly elevated
WBC at 13.1. Electrolytes and liver function tests were within
normal limits. Serum amylase was elevated at 641 U/L (normal
30-110 U/L). An abdominal ultrasound was performed and revealed
a 7 cm retroperitoneal inhomogeneous hypoechoic mass in the
left upper quadrant. It was unclear whether this lesion was
arising from the left adrenal or the pancreas. The patient
subsequently had a CT of the abdomen that confirmed the presence
of a homogeneous mass lesion with rim enhancement in the left
upper quadrant, most likely arising from the pancreatic tail
(Figures 1 and 2). No abnormal lymphadenopathy or ascites
was noted. The patient was then referred for EUS evaluation
and possible EUS-guided FNA of this mass lesion.
Linear array EUS identified a 72mm by 60
mm inhomogeneous hypoechoic round mass lesion with smooth
margins in the region of the pancreatic tail (Figure 3). Along
the anterior edge of the lesion was a 30mm by 25 mm anechoic
structure which carried an arterial doppler signal (Figures
4, 5, and 6). This was demonstrated on EUS to be an aneurismal
dilatation of the splenic artery as it could be followed continuously
back to the celiac trunk medially and to the spleen laterally.
A 7mm by 6 mm hyperechoic shadowing area of calcification
was within the aneurysm (Figure 7). This mass lesion was displacing
the splenic vein posteriorly without invading it. It was felt
that the “mass” most likely represented a contained
hematoma or a pseudoaneurysm, rather than a pancreatic mass.
Thus, fine needle aspiration of the lesion was not performed.
The patient was referred for surgical resection
of the splenic artery aneurysm. A distal pancreatectomy and
splenectomy were necessary since the lesion could not be separated
from the pancreatic tail. After further dissection, a defect
1cm in length was found in the splenic artery leading into
the aneurysm. On final surgical pathology, the “mass”
lesion was confirmed to be a large hematoma; the resection
portion of the pancreas and the spleen were normal.
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Figure
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Figure
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Figure
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Discussion/Summary
Statement
Primary splenic artery aneurysm is an uncommon
vascular pathology, with incidence of 0.01% to 0.2% reported
at autopsy series (1-3). It accounts for up to 60% of all
visceral artery aneurysms (1,4). There is a female predominance,
with the mean age of presentation at 52 years (1, 5-8). They
are usually saccular, and the majority of them are located
in the mid to distal splenic artery. (1, 6-8). The pathogenesis
of splenic artery aneurysm is not fully understood. However,
there are close associations with medial fibrodysplasia, multiple
pregnancies, portal hypertension, liver transplant, and splenomegaly.
Atherosclerosis and inflammation are often seen histologically;
although they are most commonly secondary events resulting
from primary degeneration of the media.
Most patients are asymptomatic, with aneurysm
found incidentally on imaging studies. Up to 20% may present
with epigastric or left upper quadrant abdominal pain (1,
9). Occasionally, the aneurysm can erode into an adjacent
viscus or into the pancreatic duct and presents as gastrointestinal
hemorrhage (3). Rupture of the aneurysm causes severe abdominal
pain and hypovolemic shock. The initial rupture may be tamponaded
within the lesser sac, with free intraperitoneal hemorrhage
ensuing in minutes to hours. This double-rupture phenomenon
allows valuable time for diagnosis and surgical intervention.
The reported risk of rupture varies from
3% to 10%, with a significant mortality rate of 36% after
rupture. The risk of rupture is much higher during pregnancy
and results in a maternal and fetal mortality rate of 70%
and 95%, respectively (1-3, 6, 8-11).
Treatment is recommended for all patients
with symptomatic or growing aneurysms and for all pregnant
women and women of childbearing age who may subsequently become
pregnant. Elective therapy should also be considered for good
surgical candidates with large aneurysms (> 2cm) since
they carry a higher risk of rupture (1, 2, 4-6, 8, 10, 12).
Surgical treatment options include aneurysm resection or simple
ligation. Depending on the location of the aneurysm, splenectomy
and distal pancreatectomy may be necessary. Percutaneous transcatheter
embolization, with success rate of over 80%, offers an attractive
alternative to surgery, especially for patients with high
surgical risk (6, 13, 14).
This case demonstrates how EUS could be
used to safely and efficiently diagnose splenic artery aneurysm,
which was subsequently confirmed at surgery.
References
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