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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_907_Библиотеки_им_академика_М_И_Перельмана
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performed but all areas of necrosis, identified by
preoperative CT, need to be addressed. Postoperative
closed irrigation with JP drains placed into the lesser sac
through separate small incisions should be considered in
patients with ongoing necrosis.
Postoperative Management
Postoperative complications are common and significant.
They include organ failure, retroperitoneal and intraabdominal hemorrhage, endocrine dysfunction, and
secondary fungal infections. Fistulae from the pancreatic
duct and gastrointestinal tract, pseudocyst formation,
pancreatic abscess, and vascular complications (e.g.,
mesenteric or splenic venous thrombosis and arterial
pseudoaneuryms) are also late complications of acute
pancreatitis. Follow-up with repeat imaging is required to
identify and manage these sequelae of pancreatic
necrosectomy.
Case Conclusion
The patient underwent pancreatic necrosectomy via a
vertical midline incision. His abdomen was left open
and he returned to the operating room for two additional
irrigation and debridement procedures. He tolerated
these procedures well. During the second take-back,
he underwent placement of a feeding jejunostomy, and
his abdomen was closed. Postoperatively, he remained
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hemodynamically stable and was successfully weaned
from the ventilator. Follow-up imaging was notable for
the development of a pancreatic pseudocyst, which
was managed via endoscopic cystogastrostomy. He
was ultimately discharged from the hospital to a
subacute care facility, on tube feeds, and starting to
tolerate a small amount of oral intake.
TAKE HOME POINTS
Postpyloric enteral feeding is the preferred method of
nutritional support.
Patients with acute necrotizing pancreatitis and a
question of infection should undergo CT-guided FNA
of necrotic regions of the pancreas to differentiate
between sterile and infected pancreatic necrosis.
Infected pancreatic necrosis in patients is an
indication for intervention, including radiologic
drainage and/or surgery.
Surgical intervention should favor an organpreserving
approach. Resection procedures such as partial or
total pancreatectomy that remove vital pancreatic
tissue are associated with postoperative exocrine
and endocrine insufficiency and high mortality rates.
Cholecystectomy should be performed when safe to
avoid recurrence of gallstone-associated
pancreatitis.
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SUGGESTED READINGS
Ashley SW, Perez A, Pierce EA, et al. Necrotizing pancreatitis: a
contemporary analysis of 99 consecutive cases. Ann Surg.
2001;234:572–580.
Baron TH, Morgan DE. Acute necrotizing pancreatitis. N Engl J Med.
1999;340:1412–1417.
Clancy TE, Benoit EP, Ashley SW. Current management of acute
pancreatitis. J Gastrointest Surg. 2005;9:440–452.
Connor S, Alexakis N, Raraty GT, et al. Early and late complications after
pancreatic necrosectomy. Surgery. 2005;137:499–505.
Dellinger EP, Tellado JM, Soto NE, et al. Early antibiotic treatment for
severe acute necrotizing pancreatitis: a randomized, double blind,
placebo-controlled study. Ann Surg. 2007;245:674–683.
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27
Incidental Liver Mass
SHAWN J. PELLETIER
Presentation
A 38-year-old woman with a history of a thyroid nodule
and use of an ethinyl estradiol and etonogestrel vaginal
ring presents with epigastric pain and early satiety. She
states her pain has been present for months but now
has increased in severity and limits her quality of life.
On physical exam, she is noted to have epigastric
fullness and mild epigastric tenderness. An ultrasound
of her liver demonstrates an incidental 15-cm mass in
the left lateral segment of her liver.
Differential Diagnosis
The potential differential diagnoses are listed in Table 1.
Most incidental liver masses identified in an otherwise
healthy individual are benign, but the possibility of a
malignant etiology needs to be investigated. While most
metastatic liver masses come from a colorectal origin,
neuroendocrine tumors and other cancers are possible. In
addition, primary liver cancers should be considered
including hepatocellular carcinoma (HCC),
cholangiocarcinoma, and gallbladder cancer.
TABLE 1. Differential Diagnosis of Incidental Liver Mass
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The most likely etiology of the tumor described in this
patient setting is one of several benign tumors. Cavernous
hemangiomas are benign vascular lesions of unclear
etiology. They are the most common benign liver tumor and
can be found in all age groups. Hemangiomas >4 cm in
diameter have been termed “giant hemangiomas.” Eleven
to fourteen percent of cases may be symptomatic.
Regardless of size, the risk of rupture and hemorrhage is
minimal. In rare cases, large cavernous hemangiomas may
lead to high cardiac output heart failure or Kasabach-
Merritt syndrome.
Focal nodular hyperplasia (FNH) is the second most
common benign lesion. In general, FNH is viewed as
hyperplastic and not neoplastic. Recent studies
demonstrate that these evolve from portal tract injury that
leads to oxidative stress and activation of hepatic stellate
cells forming a central scar. FNHs are typically found in
women between the ages of 30 and 50 years. There is
some association with the use of oral contraceptives, but it
is felt that the use of oral contraceptives has a low
likelihood to lead to progression.
Hepatocellular adenomas are typically found in women
between 30 and 50 years and can enlarge particularly with
the use of oral contraceptives or during pregnancy. Hepatic
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the use of oral contraceptives or during pregnancy. Hepatic
adenomas tend to have more heterogeneous imaging
characteristics. In general, the management of adenomas
is more aggressive than most other benign lesions
because rupture and hemorrhage have been reported to
occur between 11% and 29% of cases and the risk is
greatest if the tumor is more than 5 cm in diameter.
Malignant transformation into HCC has also been reported
to occur in up to 5% to 10% of lesions. Liver adenomatosis
can occur and has been previously defined as having more
than 3 to 10 adenomas.
Workup
The algorithm for the evaluation of a patient with a liver
mass is depicted in Figu re 1. Laboratory evaluation
includes a complete blood count, coagulation studies,
hepatitis screen, liver function tests, and tumor markers
(CEA, AFP, CA-19-9).
FIGURE 1 • Algorithm for evaluation of a liver mass.
Incidental solid and cystic lesions within the liver are
being detected more commonly due to increased utilization
of modern imaging. In otherwise healthy individuals, most
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incidental masses are benign. Radiologic characteristics
and clinical features can often define the etiology of the liver
mass, thus reducing the need for percutaneous biopsy.
However, after adequate imaging has been performed,
10% of lesions that remain indeterminate may be
malignant. Obtaining an accurate diagnosis is critical
because management ranges from observation to surgical
resection.
The patient undergoes further evaluation of this liver
mass with a multiphasic liver MRI, which reveals a 15-cm
mass arising from the left lateral segment of the liver,
displacing the spleen and the stomach. In addition, four
lesions, all <2 cm in size, are noted in the right lobe of her
liver (Figure 2). These lesions have peripheral nodular
enhancement during the arterial phase of the MRI and
progressive centripetal enhancement during the venous
phase. All lesions are consistent with cavernous
hemangiomas.
FIGURE 2 • Dynamic contrast-enhanced MRI of a 38-year-old woman with a
liver mass.
Diagnosis and Treatment
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Once adequate imaging is obtained, if a diagnosis of FNH
is made, the patient can be observed. If an FNH liver mass
is symptomatic and no other cause for the symptoms can
be identified, resection may be considered. For most
hepatic adenomas, consideration should be given to the
risk of resection compared to serial imaging. Adenomas
with a diameter >5 cm have an increased risk of
hemorrhage or malignant transformation. Therefore,
resection is preferred if it can be performed safely.
If the diagnosis is uncertain after adequate imaging,
consideration can be given to obtaining a percutaneous
core liver biopsy. Biopsy should be performed only when
the results will change management. In other words, if the
lesion is symptomatic or has radiologic findings concerning
for malignancy, proceeding with resection without biopsy is
reasonable. In general, biopsies can be obtained safely in
most clinical settings and have an approximate 1% risk of
either bleeding or peritoneal seeding if the tumor is
malignant. Also, because the histologic architecture is
necessary for the diagnosis of many of these lesions,
obtaining a fine needle aspiration is often unhelpful. If the
diagnosis remains indeterminate after biopsy, resection
should be performed.
Some authors have suggested that a laparoscopic
approach to liver tumors is associated with an easier
recovery and therefore may expand the indications for
surgical resection. However, even with a laparoscopic
approach, the risk of complications remains and many of
these lesions have a low risk for developing malignant
degeneration or bleeding. In addition, an operation
performed for pain from a liver tumor may be associated
with postoperative pain as well and patient selection for this
indication is critical.
Overall, significant advances have been made with liver
surgery so that mortality rates are often reported to be <2%
and even as low as 0.2% in some populations. This is
partly due to improvements in anesthesia and critical care
as well as an increased understanding of intrahepatic
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anatomy. Preoperative and intraoperative imaging,
including intraoperative liver ultrasound, allows for better
preoperative planning and performing segmental
resections. Performing portal vein embolization of the
affected side may allow for hypertrophy of the future
surgical remnant in highly selective cases. In addition, the
development of “bloodless” liver surgery has improved
outcomes using techniques such as intermittent inflow
occlusion (Pringle maneuver), isohemodilution, total
vascular isolation, maintenance of low central venous
pressures, and improved dissection instruments (hydrojet
dissection, ultrasonic dissection, saline-cooled
coagulation, bipolar cautery, surgical stapling techniques,
among others), argon beam coagulation, and fibrin
sealants.
Surgical Approach
Laparoscopic Resection
To perform laparoscopic liver resection safely, the surgeon
must have extensive experience with both open liver
surgery and advanced laparoscopic techniques. In general,
experience can be accumulated by starting with peripheral
lesions within the left lateral segment or on the inferior
aspect of the liver. As skills develop, resection of lesions
within segments five and six can be attempted. Resection
of tumors within segments seven and eight are more
difficult but can be performed safely with appropriate
experience. Ultimately, more than 75% of all patients with
liver tumors can be approached with a laparoscopic
technique, even including trisegmentectomy. As with any
laparoscopic procedure, a surgeon should not hesitate to
convert to an open procedure if there is inadequate
exposure, hemorrhage, or concern for obtaining an
adequate surgical margin.
While laparoscopic liver resections can be performed
using a straight laparoscopic or hybrid approach, the handassisted approach offers many advantages. This allows for
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palpation and direct examination of the liver and abdominal
cavity, adequate retraction of the relatively large liver, an
improved ability to obtain a negative margin, and the ability
to manually control hemorrhage. The patient is placed in the
supine position and adequately secured to the table to
allow for steep reverse Trendelenburg and rotation of the
operative table. The hand-assist device is almost always
placed in the midline near the umbilicus. For lesions in the
superior aspect of the liver, the hand-assist device may be
placed slightly higher on the abdomen. Positioning of the
trochars depends on the location of the tumor for resection
but attention should be paid to placing 12-mm trochars
strategically so that laparoscopic staplers can be utilized.
After the liver and the abdomen are visually inspected and
palpated, ligamentous attachments are divided. An
intraoperative liver ultrasound is performed, using either a T
probe through the hand port or a laparoscopic ultrasound
probe. Attention is first turned to a formal evaluation of the
liver with particular attention paid to identifying lesions
within the liver that were not identified on preoperative
imaging. The known lesion is then evaluated and the
vascular and biliary anatomy are noted. Margins for
resection can be marked on the capsule of the liver using
cautery. For lesions that are very close to major vascular or
biliary structures and the lesion is known to be benign,
consideration can be given to enucleating the tumor near
these areas. If the tumor is concerning for malignancy, a
margin should be obtained. Intermittent inflow occlusion can
be utilized by placing a Penrose drain around the porta
hepatis. The liver parenchyma is then divided using any of
a number of different techniques, such as using ultrasonic
dissection until major vascular structures are encountered.
Small- to medium-sized vascular structures can be clipped
and divided. Larger vascular structures and the portal plate
are usually divided using an endovascular stapler. The
tumor can then be removed via the hand port. Hemostasis
on the cut edge of the liver can be obtained using the argon
beam coagulation or standard cautery. The cut edge of the
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