Healthcare Professionals

Pathology

Malignant neoplasms of ductal origin are the most common of all the different types of pancreatic cancer. Acinar, endocrine and other types of tumors are less common.

• Pancreatic ductal adenocarcinoma

Approximately 90% of the cases of pancreatic cancers are pancreatic ductal adenocarcinomas (PDAC) and are mainly seen in older patients. PDAC presents itself as a malignant tumor, characterized by ill defined infiltrating masses and glandular structures, mucin formation, expression of mucin related glycoproteins and marked desmoplasia is also observed. Most PDAC's are located in the pancreatic head but can also occur in the body or in the tail or may diffusely involve multiple parts of the pancreas. Adenocarcinoma appears like firm, poorly defined white-yellow masses.

Infiltrating ductal adenocarcinomas are generally characterised by three features at the microscopic level. Firstly by definition, the neoplastic cells show glandular/ductal differentiation. Secondly they induce an intense nonneoplastic desmoplastic stromal reaction. The stoma contains myofibroblasts, lymphocytes, extracellular collagen, and trapped non-neoplastic pancreatic tissue, including trapped islets of Langerhans. Thirdly, it is characterised by infiltrating ductal carcinoma. The infiltrative growth is seen as a haphazard arrangement of the neoplastic glands extending to the adjacent structures like duodenum, the stomach, the adrenals and the peritoneum.²

Osteoclast- like giant cell tumors (anaplastic carcinoma), mucinous noncystic adenocarcinoma and signet- ring cell carcinoma are examples of variants of ductal adenocarcinoma.

• Cystic neoplasms of the pancreas

The cystic neoplasms of the pancreas include mucinous cystic neoplasms, intraductal papillary mucinous neoplasms (IPMNs), serous cystic neoplasms and solid and pseudo papillary neoplasms.

• Mucinous cystic neoplasms- These are more often seen in women (about 90%) compared to men. They arise predominantly at the tail of the pancreas and are mainly composed of large cysts that contain thick tenacious mucin. The cysts are lined in a columnar mucin-producing epithelium fashion, and the stroma surrounding the cysts has a histologic look, similar to ovarian stroma. The 5-year survival rate for patients with a completely resected invasive mucinous cystadenocarcinoma is about 50%.
• IPMNs- These neoplasms also secrete mucin but they mainly involve larger pancreatic ducts and lack a distinctive stroma. Since the larger pancreatic ducts are involved, mucin is seen to ooze from a patulous ampulla of Vater on endoscopy. IPMNs are composed of papillae lined by tall columnar mucin-producing epithelium. The 5-year survival rate for patients with resected invasive carcinomas is approximately 40%.
• Serous cystic neoplasms- These are benign tumors occurring at an average age of 65 yrs. The male to female ratio is 3:7. Serous cystic neoplasms appear as well demarcated and are composed of multiple cysts often as a scar. Microscopically the cysts are cuboidal with uniform centrally placed nuclei and a clear cytoplasm. These neoplasms can be observed and surgical resection can be offered only in case of doubt or when changes suggest a malignant transformation.
• Solid pseudo papillary neoplasms- Mostly occur in young women in the average age group of 26 years. They present themselves as well demarcated and are grossly composed of solid and with cystic areas showing haemorrhage and necrosis. Microscopically, the solid areas are made up of sheets of relatively uniform cells and delicate blood vessels. Surgical resection is associated with long term survival.

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