Pancreas Flashcards
Recap of pancreas?
The pancreas is a transversely oriented retroperitoneal organ. It is a heterocrine gland which means it has two components.It has an exocrine portion which occupies 80 to 85% of the organ composed of acinar cells which contain proenzyme and an endocrine portion which is composed on clusters of cells called islets of langherhans which secrete insulin, glucagon and somatostatin.
What are cystic neoplasm of the pancreas?
They are diverse tumors that range from harmless to lesions that might be precursors. Like serous cystic and mucinous cystic.
What is serous cystic neoplasm?
Composed of multiple small cysts lined by glycogen rich cuboidal cells contains serous fluid. Usually found in the tail or head of the pancreas. They have a great prognosis as they are almost always benign.
What are mucinous cystic neoplasms?
They are pre malignant cysts usually in the tail of the pancreas. They are painless slow growing in masses with cavities containing mucin and lined by columnar mucin producing epithelium. KRAS, TP53 and RNF43 are frequently found. 1/3 of resected cysts had an adenocarcinoma.
What are intraductal papillary mucinous neoplasms?
They are pre malignant neoplasms composed of mucin producing cells. They are more frequently found in the head and are involved with larger ducts. Does not present ovarian like stroma unlike mucinous cystic neoplasms. Branch type is not resected, main duct type is resected due to risk of carcinoma and mixed type.
What are pseudopapillary neoplasms?
They are rare large well circumscribed mostly benign neoplasm with solid and cystic components filled with hemorrhagic debris due to abundant vascularization.They often cause abdominal discomfort due to the size and the treatment choice is surgical resection which leads to cure most patients.
What is pancreatic carcinoma?
Infiltrating ductal adenocarcinoma of the pancreas is the fourth leading cause of cancer deaths in the USA and has a five-year survival rate of 5%. They usually present as hard, gray white, poorly defined masses; 60% of cancers arise in the head, 15% in the body, 5% in detail and then 20% of the cases it is diffused. Most Carcinomas of the head to obstruct the distal common bile duct causing jaundice. Carcinomas of the body and tail do not cause jaundice hence remain silent. Histologically there is no difference between carcinoma of the head and those of the body and tail.The appearance is usually poorly differentiated adenocarcinoma forming tubular structures and cell clusters. The strongest risk factor is cigarette smoking, other factors are obesity, chronic pancreatitis and diabetes mellitus. It’s arises by precursor lesion known as has pancreatic intraepithelial neoplasia.
What are some important genes implicated in pancreatic carcinoma?
KRAS : Most frequently altered oncogene in pancreatic cancer. It is a protein that participates in signaling events downstream of growth factors and pathways that augment cell growth and survival.
CDKN2A : It is inactivated in 95% of pancreatic cancers. It encodes for tumor suppressors and activation of p53.
SMAD4 : Tumor suppressor gene inactivated in 55% of pancreatic tumors. It encodes for signal transduction.
TP53 : inactivation of this tumor suppressor occurs in 70% of pancreatic tumors.
What is pancreatoblastoma?
Very rare Malignant and Neoplasm occurring primarily in children. Usually affects the head of the pancreas. Despite their malignancy their survival is better than pancreatic duct adenocarcinoma.
What is Acinar cell carcinoma?
It is an aggressive tumor which gives non-specific symptoms. 15% of individuals develop the syndrome of metastatic fat necrosis caused by release of lipase into the circulation.
What is a neuroendocrine neoplasma?
Also known as pancreatic neurocrine tumors, PanNETs. They are much rarer than exocrine tumors, 2% of all pancreatic tumors. They can occur anywhere along the length of the pancreas.They can either be functional and elaborate Pancreatic hormones or non-functional.
What is an Insulinoma?
Beta cell tumors are the most common on PanNETs. They are generally benign but can produce sufficient insulin to induce hyperinsulinism with clinically significant hypoglycemia. They are small solitary Tumors which are in capsulated, pale to red brown Nodules located anywhere in the pancreas. Histologically they resemble giant islets.
Gastrinoma?
Gastrin producing tumor. They can arise in the pancreas as well as in the duodenum. They are much more malignant than insulinomas. Increased secretion of gastrin causes Zollinger Ellison syndrome characterized by gastric acid hypersecretion. Jejunal ulcers are common also diarrhea.
What are ampullary neoplasms?
They are gland forming malignant epithelial and neoplasms originating in the ampullary complex. The most common type is adenocarcinoma which can be classified into two major groups: Intestinal Type (CD20+ and CK7-) which is confined within the intestinal wall and Pancreatic Biliary Type (CD20- and CK7+) which usually infiltrates pancreatic parenchyma.
