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PANCREATITIS
43
demonstrate the communication and under these circumstances cyst aspira-
tion will be necessary (see Table 1.4 ).
When a diagnosis of a pancreatic cystic tumour has been made with confi-
dence, then our approach to all of these is identical and they should, if possible,
they be resected. In elderly and unfit patients this may not be appropriate
(especially with small cysts or an equivocal diagnosis).
Unfortunately, although the diagnosis is generally clear there remains a
small cohort where this is not the case (see Table 1.5 ).
Equivocal lesions will have to be observed for radiological change, princi-
pally increase in size or change in appearance ( Table 1.6 ).
When a diagnosis has been made it is important preoperatively to obtain a
good quality abdominal CT scan, CA 19.9 estimations, laparoscopy, and
intraoperative ultrasound to ensure that there is no dissemination which
unfortunately often occurs at an early stage. When investigations have not
revealed any extrapancreatic disease we perform a formal resection based on
the tumour site. As the majority are in the body or tail of the gland this usually
involves a distal or subtotal pancreatectomy and splenectomy. Patients requir-
ing distal pancreatectomy should always have a splenectomy to obtain ade-
quate clearance and allow a full formal lymphadenectomy. These patients are
immunized against Haemophilus infl uenzae (type b), Neisseria meningitidis ,
and S treptococcus pneumoniae 2–3 weeks prior to their procedure.
Subtotal pancreatectomy or pancreaticoduodenectomy is occasionally
required but should only be performed for lesions considerably to the right of
the portal vein.
Distal pancreatectomy
The operation of distal pancreatectomy covers a variety of procedures from
resection of a small amount of the tail to treat a fistula, to subtotal resections for
Table 1.5 Comparison of the findings in a pseudocyst and pancreatic cystic tumour
Pseudocyst Cystic tumour
Previous pancreatitis or trauma
Single cyst, non-loculated
No septae, wall < 5mm
Duct cyst communication > 65%
Low viscosity fluid with raised amylase
Inflammatory cytology
Cyst wall histology shows fibrotic changes only
No previous history
Multiloculated
Thick walled
No duct to cyst communication
High viscosity fluid with low amylase
Malignant cytology with raised tumour
markers
Malignant or premalignant cells
PANCREAS
44
Fig. 1.27 Investigation and management of cystic lesions of the pancreas.
Pain, bilary
observation or
incidental finding
CT, MRI & clinical
hist
Thick walled mucin
solid component
CEA elevated CA 19.9
elevated cytology
abnormal high mucin
content or viscosity
Indeteminate
features
EUS/FNA
Equivocal
Observe bimonthly CT
to 2 years then
annually
Increase in size
symptomatic
abnormal FNA
<3cm symptomatic
Repeat EUS/FNA
Mucinous cystic
neoplasm
Solid pseudo
papillary tumour
Cystic degeneration
of solid tumour
IPMN
Side branch Main branch Resection
Observation
unfit/elderly
>3cm symptomatic
fit & young patient
Unilocular cyst
history of
pancreatitis
Pseudocyst
6 weeks duration ±
symptomatic
Laproscopic open or
endoscopic
drainage. Cyst wall and
contents analysis
Clinical doubt
Microcyst with
central scar
EUS/FNA
EUS/FNA
2-yearly scan
Symptomatic
>4cm diameter
Resection after
careful counselling
Asymptomatic
unfit
<4cm
Serous
cystadema
PANCREATITIS
45
awkwardly placed lesions to the right of the portal vein. It can also be indicated
for multiple lesions most commonly found with endocrine tumours. The only
variations of the procedure are related to the pathology. For resections in chronic
pancreatitis to remove a diseased portion of the gland, or a gland that has been
replaced by (or contains) a refractory pseudocyst, the splenic artery and vein and
spleen can generally be preserved. We are willing to sacrifice the splenic artery
and preserve the spleen but less so the vein as postoperative problems generally
relate to venous congestion, not to an inadequate arterial supply. In malignant
disease, the splenic artery, splenic vein, and spleen should always be resected en
bloc with the pancreas. The operative strategy contains features that we always
employ, the operation being performed through a transverse incision and the
omentum fully mobilized from the transverse colon and splenic flexure.
Spleen-preserving distal pancreatectomy for benign disease ( Figs. 1.28 –
1.33 ) After mobilizing the splenic flexure, an excellent view of the body and
the tail of the pancreas and spleen is obtained.
It is generally necessary to free a few adhesions between the stomach and
pancreas but at this stage the splenic artery, coeliac trunk, and lower border of
the pancreas can all be identified. Dividing the gastrocolic ligament exposes
the tail of the pancreas and the termination of the splenic artery and vein in the
splenic hilum.
Table 1.6 Important points to remember when assessing a cystic pancreatic lesion
for malignancy or malignant potential
Cystic lesions of the pancreas, even when found incidentally, require diagnostic evaluation
regardless of size because they may represent premalignant or malignant lesions (Brugge
et al ., 2004a )
EUS findings alone are not sufficiently accurate to make a definitive diagnosis of the type
of cystic lesion of the pancreas or to determine if is malignant or has malignant potential
(Brugge et al ., 2004b )
Although cytological analysis of cyst fluid obtained by EUS and fine-needle aspiration
(FNA) lacks sensitivity, it has a high specificity for mucinous cystic neoplasms and
malignancies (Brugge et al ., 2005 )
The examination of pancreatic cyst fluid should include staining for mucin (Leung et al .,
2007 )
Measurement of cyst fluid amylase, lipase, and tumour marker concentrations may
offer clinically useful information. They cannot, however, provide a definitive diagnosis
or determine with certainty if the lesion is malignant (Van der Waaij et al ., 2005 ;
Pelaez-Luna and Chari, 2006 ; Maker et al ., 2008 )
Finding a patulous ampulla (pancreatic orifice specifically) extruding mucin during ERCP
for evaluation of a cystic lesion of the pancreas is specific but not sensitive for IPMT
(intraductal papillary mucosal tumour) (Sohn et al ., 2001 ; Reddy, 2004 )
PANCREAS
46
Fig. 1.28 The omentum is freed from the transverse colon to expose the body and
tail of the pancreas.
Fig. 1.29 The gastrosplenic
ligament is divided.
PANCREATITIS
47
Fig. 1.30 The neck of the gland is mobilized and slung just to the left of the
portal vein.
Fig. 1.31 After freeing a sufficient length of pancreas by division of branches of the
splenic artery and tributaries of the splenic vein the gland is transected with a linear
stapler.
PANCREAS
48
In operations for benign disease, avoid mobilizing the spleen leaving all the
peritoneal attachments intact.
At this stage, we identify the plane behind the pancreas and vessels just to the
left of the portal vein and the origin of the splenic artery. The neck of the gland
Fig. 1.33 The head of the gland is examined and if the pancreatic duct is found it is
ligated or clipped. The gland is then oversewn.
Fig. 1.32 Dissection continues until the pancreas is completely free and can be
removed. All tributaries and branches are transfixed.
PANCREATITIS
49
is then slung which acts as an excellent anatomical landmark and enables
control of bleeding if necessary.
With a distal resection for benign disease, the splenic artery and vein must
then be freed sufficiently from the gland to allow it to be transected.
Depending on the pathology (single neuroendocrine tumour or previous
pancreatitis with pseudocyst), this can be relatively straightforward or very
challenging.
Depending on the consistency of the gland, we will decide whether stapling
is appropriate. In a gland which is normal and soft the stapler cuts through the
parenchyma, does not control bleeding, and makes the duct very difficult to
identify. In these patients we transect by hand, identify the duct and ligate or
tie it, and then oversew the remnant ( Fig. 1.33 ).
However, if the gland is firm and atrophic then the duct can be difficult to
locate and transection with a stapler is preferred. The splenic artery and vein
can then be carefully dissected from the gland and all the tributaries and
branches ligated (or clipped) and oversewn. The dissection continues until it
reaches the tail of the gland in the splenic hilum and the pancreas can then be
removed. Haemostasis is checked and the spleen carefully examined to assess
its viability. We will sacrifice the splenic artery if essential but are very reluctant
to damage or ligate the splenic vein as in our experience, problems result from
venous congestion (both in the immediate postoperative period and long term
with increase in size of the spleen). The short gastric arteries are almost always
adequate to prevent ischaemia.
Distal pancreatectomy for malignant disease ( Figs. 1.34 and 1.35 ) Exposure
and mobilization of the pancreas are initially the same as for benign disease
and again we place a sling around the neck of the gland just to the left of the
portal vein if this is sufficiently proximal to the tumour. With malignant
lesions, at this stage we would also search for evidence of lymph node involve-
ment (frozen section examination of suspicious nodes is essential). A positive
finding is a contraindication to resectional surgery. In the absence of dissemi-
nation, the spleen and tail of the pancreas are then fully mobilized. Depending
on the site of the lesion the resection margin is planned to give at least 2cm
clearance proximally.
This is frequently very close to where the gland has already been slung
and the previous mobilization facilitates the identification of the splenic
vessels which are ligated, divided and transfixed with 4/0 prolene. Again,
transection of the pancreas depends on the nature of the gland (and the
principles are the same as those described for benign disease) and dissection
proceeds, again as for benign lesions, towards the spleen. Mobilization of
the spleen and tail of the pancreas allows the dissection to remain in the
PANCREAS
50
Fig. 1.34 After initial examination of the tumour and frozen section biopsies of any
abnormal or suspicious lymph nodes, peritoneal, or serosal nodules, the neck of the
gland is mobilized and slung just to the left of the portal vein.
Fig. 1.35 The splenic artery and vein are ligated, divided, and transfixed and the
pancreas transected with a stapler at least 2cm proximal to the tumour. Mobilization
is completed by dissection in the plane behind the splenic artery and vein and
removing all fatty and lymphatic tissue en bloc. The head of the gland is over-sewn
as shown in Fig. 1.33 .
PANCREATITIS
51
correct plane below the vessels and all lymphatic and fatty tissue must be
resected en bloc.
The distal pancreas and spleen are then removed and the divided end of
pancreas oversewn. After a thorough washout, two tube drains are inserted and
the abdomen is closed. There are potential consequences to splenic resection,
particularly the increased susceptibility to infection (Bisharat, 2001 ). As dis-
cussed earlier, we immunize these patients preoperatively against Streptococcus
pneumoniae, Neisseria meningitidis and Haemophilus infl uenzae (type b) and
they are required to take prophylactic antibiotics for at least 5 years. This
approach dramatically reduces the complication rate, particularly the mortal-
ity rate from infectious complications which approaches zero (see Fig. 1.36 ).
Neuroendocrine tumours of the pancreas
A hormone-producing tumour was first recognized in 1902 and in 1907
Oberndorfer differentiated carcinoid tumours from carcinoma of the GI tract
(Oberndorfer, 1907 ). In 1969 Pearse described APUD ( A mine P recursor
U ptake D ecarboxylation) cells that produce hormones and amines identical to
those found in neuron/neurotransmitter junctions (Pearse, 1969 ). Lang in
1994 defined neuroendocrine cells as those that:
♦
Produce neurotransmitters, neuromodulators, or neuropeptides
♦
Have dense core secretory granules that release hormones by exocytosis
after the receipt of an external stimulus
♦
Axons and synapses are absent (Langley et al ., 1994 ).
Endocrine tumours of the pancreas have been recognized since 1920 but due
to the variety of presentations and subtle syndromes that they produce (often
over a prolonged period), a better understanding of these tumours was only
achieved much more recently when the details of the cells which make up the
system became known. Previously they were frequently classified with, or even
felt to be the same as, carcinoid tumours. Carcinoid (serotonin producing)
tumours of the pancreas are exceptionally rare, with only about 100 ever hav-
ing been reported. It is now known that the neoroendocrine cells from the
diffuse endocrine system (DES) and the gastroenteropancreatic axis (GEP)
constitute the largest endocrine organ in the body (gastrointestinal [GI] tract,
lung, liver, pancreas, ovaries, testes, and bile ducts). Neuroendocrine tumours
of the pancreas and gut originate from the DES and are now called GEP–NETs.
It is interesting in this respect to contrast the World Health Organization
(WHO) classifications for neuroendocrine tumours in 1980 and in 2000 (Solcia
et al ., 2000 ). The recent classification describes them on the basis of site of
origin, malignant potential, and functional activity, which is clearly much
more useful in the clinical setting ( Table 1.7 ).
PANCREAS
52
Fig. 1.36 Indications and consequences of splenectomy.
Therapeutic
latrogenic
25%
Trauma
Total
splenectomy
Suture repair
Partial
splenectomy
Delayed
rupture
‘Spontaneous’
rupture
Non−operative
Mortality
10−50%
Mortality 5%
Mortality 5%
Incidence 4%
Incidence 1%
Incidence?
Lifelong risk
Untreated
Antibiotics
Sepsis
Success
90−95%
80%
90%
3−4%
10−15%
Splenosis
Mortality
Complications
2%
Immunise
Splenectomy