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An approach to reporting of pancreatic specimen
;
Reporting of ampullary and periampullary biopsies
for the diagnosis of neoplastic lesions
;
Reporting of Pancreaticoduodenectomy (Whipple's
operation) specimen
;
Reporting of Distal Pancreatectomy Specimen.
These are almost
always taken for lesions of the exocrine pancreas.
Chronic
pancreatitis can mimic neoplasia clinically and radiologically as it may
form a mass in the head of the gland.
On biopsy similar
confusion can arise : Pancreatic adenocarcinoma is often
desmoplastic and can closely resemble chronic pancreatitis in which
there is distortion of acni and ducts by dense fibrosis.
Visit:
Pancreatic Pathology Online
;
Exocrine Pancreatic Tumours.
.
Microscopical report :
If a neoplasm is
present, the report should comment on the:
Type:
- Cystadenoma :
Microcystic ; Serous ; Mucinous ;
- Adenocarcinoma
and subtypes : Adenosquamous ; Mucinous ; Papillary cystic ;
-
Anaplastic
carcinoma ;
- Acinar cell
carcinoma ;
- Squamous cell
carcinoma (probably metastatic) ;
- Giant cell tumour
;
- Pancreatoblastoma
;
- Lymphoma (NHL or
Hodgkin's).
Differentiation:
Spread:
Perineural ; Intravascular ; Extrapancreatic;
Associated
inflammatory changes.
When no-neoplastic
tissue is present in the biopsy, the report should commont on the
appearances of the:
Acini:
Dilatation, atrophy, necrosis ;
Ducts:
Dilatation, hyaline
casts, periductal fibrosis, inflammation, squamous metaplasia ;
Vessels:
Vasculitis ,
necrosis, thrombosis ;
Inflammation:
Acute, active,
chronic, granulomatous ;
Hemorrhage:
Diffuse or
focal ;
Fibrosis:
Site and
extent ;
Calcification:
Site,
including peripancreatic tissues ;
Iron deposition:
As
seen in haemochromatosis and haemosiderosis .
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Prognostic factors:
Several prognostically important
histopathological features have been determined for pancreatic
exocrine carcinoma and these should be assessed and recorded . The
tumour type and grade should be determined. The tumour size and
distance from the anterior peritoneal surface and both the
retroperitoneal and pancreatic (if applicable) surgical margin
should be confirmed microscopically since macroscopic assessment
alone may lead to inaccuracy due to co-existent chronic pancreatitis.
The presence of lymphovascular and/or perineural tumour invasion
should be noted. The common bile duct surgical margin should
be examined for evidence of dysplasia or invasive tumour. Lymph node
status is a powerful predictor of survival and the presence, number
and position of any tumour-involved nodes should be clearly noted.
The individual components of the TNM staging system are independent
prognostic factors and therefore the TNM stage of the tumour should
be recorded. A brief description of the background gastric and
duodenal mucosa is also recommended.
Additional prognostic factors
Several
individual studies have suggested that the MIB-1 labelling index,
p53 and Bcl-2 labelling and DNA ploidy are independent prognostic
factors in pancreatic adenocarcinoma. However, these additional
techniques have yet to be adopted into routine clinical practice.
Frozen section and needle biopsy
assessment
Confident
distinction of well differentiated adenocarcinoma from chronic
pancreatitis may be very difficult in these small specimens and the
two conditions frequently co-exist. A firm diagnosis may not always
be possible. Features favouring malignancy include marked nuclear
size variation between ductal epithelial cells, incomplete ductal
lumens, disorganized ductal distribution, large irregular nucleoli,
necrotic glandular debris, glandular mitotic figures and perineural
invasion. |
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Rarer forms of pancreatic exocrine carcinoma
include adenosquamous carcinoma, pleomorphic giant cell carcinoma (an
anaplastic tumour in which there are malignant giant cells) and osteoclast-like giant cell tumour (a malignant anaplastic epithelial
tumour admixed with osteoclast-like giant cells). Analysis of such
tumours for mutations of the Ki -ras oncogene suggests that they are
variants of pancreatic adeno-carcinoma with a similar prognosis.
Acinar cell carcinomas are very rare.
Macroscopically there are lobules of tumour cells separated by fibrous
bands. Acinar areas, trabecular and solid areas are all found
histologically and the relatively uniform tumour cell morphology can
lead to confusion, particularly with endocrine tumours. Acinar tumors
are cytokeratin positive as well as staining for pancreatic enzymes
such as trypsin and lipase. Endocrine tumours will stain for synaptophysin and chromogranin but focal staining for these endocrine
markers can be seen in acinar tumours. Study of Ki-ras mutations
suggests that these tumors have a different histogenesis from
pancreatic ductal carcinomas although the prognosis is not dissimilar.
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