Pancreatic Pathology Online
Pathology of Ductal Adenocarcinoma of the Pancreas
adenocarcinoma accounts for about 80-90% of malignant exocrine tumours.
Etiology: Etiology is complex and probably multifocal, although smoking and a high intake of dietary fat seem important.
Familial causes are rare but pancreatic ductal adenocarcinoma may occur in some families with history of cancer.
Age and sex : Mostly seen over 50 years of age. Male: female ratio is 1.5 : 1.0
Sites and clinical features:
1. Head (two-thirds of the cases)- Causes obstruction of the biliary tract with jaundice and occlusion of the main pancreatic duct leading to obstructive pancreatitis.
2. Tail, uncinate process or in combined sites: Patients present with pain and weight loss or liver metastases from an "occult" primary.
Local spread: depends on the location of the tumour and include - From head: bile duct, duodenum and retroperitoneum. From tail: peritoneum, stomach, colon, spleen and left adrenal.
Lymphatic spread: To the Peri-pancreatic lymph nodes ;
To the regional lymph nodes (in the hepatoduodenal ligament up to the ciliac trunk) in about 50% of cases.
"Juxta-regional" - mainly para-aortic lymph nodes in about 10% of cases.
Blood-borne metastases: To the liver, lungs, pleura and bone.
Gross features : Head: Generally "solid", poorly demarcated, hard, yellowish-white to gray, often about the size of 2-5 cm in diameter.
Hemorrhage, necrosis, and cystic change is rare except in very large cancer.
Body or tail: Diffuse growth spreading in the parenchyma.
Average size is about 5-7 cm or more.
Pathological staging (TNM classification ):
I - Based on the size of the primary tumor:(pT1-pT4)
II- Presence or absence of regional metastatic lymph nodes (pN1a or pN1b), if multiple lymph nodes are involved.
III - Distant metastases (pM).
1. Well to moderately differentiated tumours : Consists of tubular and glandular structures lined by mucus-secreting columnar cells arranged in a single regular layer, but may show stratification and papillary projection. There is a marked desmoplastic reaction, with formation of dense fibrous tissue.
2. Moderately and poorly differentiated tumours: Consists of poorly formed glands with decreased mucus secretion. Pleomorphism and mitotic figures are present.
1. Antibodies to cytokeratin 7, 8, 18, and 19.
2. Epithelial Membrane Antigen (EMA)
3. Carcinoembryonic Antigen (CEA)
The majority of ductal adenocarcinomas show K-ras and P53 mutations, which differentiate it from mucinous cystic tumours, acinar cell carcinomas, and endocrine tumours, all of which lack these mutations.
1. Usually reveals remnants of lobules embedded in fibrotic tissue.
2. Remaining ducts may be dilated or atrophic.
3. Ductal epithelium may be atrophic or hyperplastic.
4. Calcification and proteinaceous plugs in the ducts are common.
Death within 3 years - 90% of cases. 5-year survival is 1 to 5%.
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