# Pancreatic Mass with an Unusual Pathology: A Case Report

Authors: Andrew J. Healey; Anna Reed; Long R. Jiao
Journal: HPB Surgery
 (2008)

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## Abstract

Intra-abdominal abscesses formation in patients
with no preceding symptoms is rare. Infection of the pancreas
occurs in 5–9% of patients with acute pancreatitis, more commonly
as a complication of necrotising or severe pancreatitis. We have
reported a case of a 64-year-old almost entirely asymptomatic man
who underwent a Whipple's procedure following extensive
investigation of a pancreatic mass. The pathology and histology
showed no evidence of malignancy, and instead a true pancreatic
abscess, centred around an impacted cholesterol calculus in the
distal CBD. Of suspicious pancreatic masses that are resected,
chronic choledocholithiasis is the aetiology in less than 5% of nonmalignant or “false positives. This report describes such a
case.


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## Body

## 1. Introduction

Although
intra-abdominal abscesses have frequently been  reported to be one of the major
complications of acute necrotizing pancreatitis, abscess formation in patients
with no preceding symptoms is rare.


## 2. Case Report

In
December 2004, a 65-year-old retired Caucasian banker attended his GP for a
checkup. He was a keen tennis player, and his general health was very good. His
daily intake of alcohol averaged 3-4 units, and he was a nonsmoker. He had
never been jaundiced or experienced abdominal pain but did describe one episode
of pyrexia coinciding with a transient period of passing dark urine. He did not
seek medical consultation at that time, and it resolved over a “day or two.”
The relevant laboratory data at his checkup were as follows: WBC, 8900/mm3;
haemoglobin (Hb), 14.2 g/dl; c-reactive protein (CRP), <2; total bilirubin,
13 μmol/L; alanine transferase (ALT), 197; alkaline phosphatase (ALP), 254 IU/L;
gamma-glutamyltranspeptidase (gammaGT), 926 IU/L; serum amylase, 65 IU/L;
carbohydrate antigen (CA)19-9, 14 U/mL; and alpha-fetoprotein, 9 IU/L. Hepatitis
serology was negative for A, B,  and C, and he had a normal clotting screen. He
was referred to a hepatologist, and subsequent abdominal ultrasound scan
revealed a biliary tree dilatation extended into the intrahepatic ducts. No
gallstone was visualised in the common bile duct (CBD). At ERCP, the CBD was
cannulated, the biliary dilation was again noted and a 2 cm-long biliary
stricture was detected (see Figure 1). No calculus was visualised, and a 10F-pigtail
biliary stent was left in situ. A CT scan on the same admission confirmed a
heterogeneous mass 2 cm in diameter in the pancreatic head (and the biliary
dilatation) (see Figure 2). An endoscopic ultrasound was performed, which was
“inconclusive,” (pictures unavailable). After discussion at the
multidisciplinary meeting, surgical resection was offered to the patient. The
patient was suitably preassessed for anaesthetic and consented for an elective
modified Whipple's procedure or PPPP. The initial findings at laparotomy were a
“grossly abnormal, thick walled and inflamed gall bladder, with impaction of
large stone at Hartmann's pouch.” Two hard nodules were palpable in the head of
the pancreas and distal CBD. The second part of the duodenum (D2) was “tethered”
to Hartmann's pouch. An open cholecystectomy and frozen sections of the gall
bladder revealed inflammatory tissue only. The PPPP was completed with
pancreaticogastrostomy, gastrojejunostomy, and choledochojejonostomy
reconstruction. Postoperatively the patient was commenced on intravenous
cefuroxime and metronidazole, and subcutaneous octeotride (100 mg).
He commenced
diet again 6 days postoperatively and was discharged home day 13, after an
uneventful recovery. The macroscopic pathological specimen is shown in Figure 3
below. It shows an impacted cholesterol calculus in the distal CBD and a cystic
cavity in the head of the pancreas from which, on sectioning, a lump of
necrotic tissue was dislodged. Histology revealed no evidence of adenocarcinoma
or chronic pancreatitis.Figure 1
ERCP films show the proximal common bile duct stricture and dilated
distal biliary tree.Figure 2
CT with contrast (arterial phase) showing the mass
at the head of the pancreas (PM) and dilated common bile duct (dCBD).Figure 3
Pancreaticoduodenectomy resection specimen, showing sectioning (in
the plane of the black dotted line) of the second part of the duodenum (D), the
common bile duct (CBD), the site of the previously impacted gall stone
calculus (IGS), the biliary stricture (blue dotted line) and pancreatic
abscess cavity (PA).


## 3. Discussion

Infection
of the pancreas occurs in 5–9% of patients with acute pancreatitis
[1].
Pancreatic abscess is also a frequent complication in patients undergoing early
operation for management of haemorrhagic or necrotizing pancreatitis, occurring
in 50–70% cases [2]. Other causes include penetrating duodenal ulcer,
infection of an established pseudocyst, pancreas divisum, and penetrating
pancreatic trauma. Clinical and experimental studies have shown a positive
correlation between the risk of pancreatic infection and the amount of tissue
necrosis which is believed to serve as a bacterial culture medium. The Atlanta
classification
attempts to clarify the terms commonly used to describe the infectious
complications of acute pancreatitis [3]. It defines pancreatic abscess
as a collection of purulent pancreatic material contained within a more-or-less
defined fibrous tissue wall. This differentiates it from infected necrosis,
(semiliquefied peripancreatic tissue with positive microbial cultures) and
infected pseudocyst (an encapsulated collection of pancreatic juice from which
bacteria can be grown). Many pancreatic abscesses in fact probably begin as
infected necrosis.The
first step in the treatment of pancreatic abscess is early accurate diagnosis.
However, clinical presentation can be variable and for this reason pancreatic
infection should be considered in any patient who shows subtle signs of
deterioration and evidence of infection weeks after an episode of acute
pancreatitis. Symptoms such as abdominal pain, nausea and vomiting, and
palpable mass are present only in a minority Indeed in this case; the only
evidence of any preceding biliary disease was a transient pyrexia and
obstructive episode that did not even precipitate the patient seeking medical
review. At no point was there abdominal pain, nausea or vomiting, or any other
symptoms suggestive of pancreatitis or chronic infection.In
a review of 442 Whipple's procedures between 1999–2001, Abraham et al. found that 9.2% were
“false
positives” (i.e., operations performed for clinically suspicious lesions) [4].
Of these, at presentation 67.5% had a mass lesion, 50% obstructive jaundice,
40% common bile duct stricture, and 12.5% suspicious cytology (note that some
had several). Again in this case, the patient was found to have both a mass
lesion and biliary stricture, but no jaundice. Histological review of resected
tissue showed 65% were a result of chronic pancreatitis, 22% were from biliary
tract disease, 5% from duodenal disease and the remainder from other causes. Of
these false positives, chronic choledocholithiasis was the aetiology in just
5%.Imaging
techniques are the gold standard for the diagnosis of pancreatic abscess. In
one study of 45 patients, CT had a sensitivity of 74% compared with 35% for
ultrasonography [5]. However, CT cannot distinguish sterile
inflammation from infection, and fine needle aspiration of the mass or
collection has been suggested to be simple and have a sensitivity of
90–100% [6].
Certainly, ERCP is increasingly being replaced by EUS and FNA in the
investigation of suspicious pancreatic lesions. In >75% pancreatic abscesses,
the bacteria recovered are usually polymicrobic, with coliforms the most
frequently isolated. Pancreatic tuberculous infection, although rare, is seen
increasingly in HIV-positive patients [7]. However in this
circumstance, there was no clinical or haematological evidence of infection,
and indeed, although the complication rate for needle aspiration is low, there
is a risk of iatrogenic introduction of infection to a sterile area.
Furthermore, in the Abraham series, the false positives, although benign, were
positive for pancreatic intraductal neoplasia (PanIN) 1A/1B in 68% and PanIN 2
in 40%.A
substantial body of evidence suggests that the risk of developing an abscess is
directly related to the severity of the underlying episode of pancreatitis. The
incidence of “major pancreatic sepsis” in 247 patients with 0–2 Ranson's signs
was 1.6% rising to 24% in 46 patients with Ranson's score of 3–7 [8].
Successful therapy of serious pancreatic infections is dependent on early
debridement and drainage. However in this circumstance, there was no previous
pancreatitis or evidence suggestive of an underlying infective process, so
neither needle aspiration or surgical debridement would represent obvious
management strategies. Certainly the failure to visualise the stone at ERCP, an
inconclusive EUS (from which cytology may have helped diagnostically) with a
concurrent biliary stricture favoured surgery in this instance.


## 4. Conclusions

Whipple's
resections for presumed malignancy have unearthed benign nonneoplastic
conditions in 5–11%. Chronic choledocholithiasis is responsible for 5% of these
“false positives.” We have reported a case of a 64-year-old man who underwent a
Whipple's procedure following extensive investigation of a pancreatic mass.
Postoperatively, the mass was shown to be a true pancreatic abscess,
complicating a chronic choledocholithiasis. This is a rare case of subclinical
pancreatic abscess, in a man with no previous symptomatic pancreatic disease or
endoscopically or radiologically identifiable biliary calculi.



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*Source: 374602-2008-05-08.xml*