Pancreatic_Gallbladder_Pathology_Flashcards
Topic
Details
Introduction
Speaker: Prof. Rob Goldin
Focus: Pathology of the pancreas and gallbladder, including inflammatory diseases, neoplasms, and related conditions.
Context: Lecture on the less frequently discussed but crucial organs in GI pathology.
Pancreas Anatomy and Physiology
Normal Structure:
- Exocrine Component: Composed of acinar cells that secrete digestive enzymes (inactive form, except lipase) into the ducts.
- Endocrine Component: Islets of Langerhans scattered among the acini, containing alpha, beta, and other hormone-secreting cells.
- Ductal System: Pancreatic duct joins the common bile duct before entering the duodenum.
- Unique Aspects: Enzymes capable of digesting proteins, lipids, and carbohydrates, posing a risk of self-digestion if inappropriately activated.
Acute Pancreatitis - Causes
Duct Obstruction: Gallstones are the most common cause. Tumors and trauma can also cause obstruction.
Metabolic and Toxic: Alcohol (common cause), hypercalcemia, hyperlipidemia, certain drugs.
Infections and Inflammation: Viruses like mumps.
Blood Supply Issues: Shock, ischemia.
Autoimmune and Idiopathic: Less common causes.
Acute Pancreatitis - Pathogenesis
Activation of digestive enzymes within the pancreas leads to self-digestion.
Positive feedback loop exacerbates damage.
Alcohol can cause sphincter of Oddi spasm and protein-rich secretions, leading to obstruction and pancreatitis.
Acute Pancreatitis - Histological Features
Patterns of injury vary based on the cause (e.g., central necrosis with duct obstruction, peripheral necrosis with ischemia).
Enzyme release leads to necrosis, hemorrhage, and systemic inflammation.
Fat Necrosis: Characteristic feature due to the action of lipase, forming calcium soaps (saponification).
Acute Pancreatitis - Complications
Pseudocysts: Fluid collections lacking epithelial lining.
Abscesses: Infected pseudocysts.
Systemic effects: Shock, hypocalcemia (due to fat necrosis), hyperglycemia, hypoglycemia.
Chronic Pancreatitis - Causes
Metabolic and Toxic: Alcohol is the leading cause.
Genetic and Obstructive: Cystic fibrosis, anatomical abnormalities, tumors.
Autoimmune: IgG4-related disease.
Idiopathic: Unclear origins.
Chronic Pancreatitis - Pathogenesis
Similar to acute pancreatitis but with progressive fibrosis.
Chronic inflammation leads to loss of exocrine and endocrine function.
Formation of strictures, stones, and atrophy.
Chronic Pancreatitis - Complications
Malabsorption: Due to loss of digestive enzymes.
Diabetes: Loss of islets of Langerhans.
Pseudocysts: Can persist and cause symptoms.
Increased risk of pancreatic cancer (controversial but noted).
Chronic Pancreatitis - Histological Features
Fibrosis replacing acinar tissue.
Remaining islets appear prominent due to loss of surrounding exocrine tissue.
Ductal dilation and stone formation.
Pancreatic Neoplasms - Types
Ductal Adenocarcinoma:
- Most common type (85% of pancreatic neoplasms).
- Arises from ductal epithelium, highly aggressive with a poor prognosis.
- Risk Factors: Smoking, chronic pancreatitis, genetic predispositions, raised BMI.
- Presents with abdominal pain, jaundice, weight loss.
- Histology: Gland-forming, mucin-secreting adenocarcinomas with desmoplastic stroma.
- Propensity for perineural invasion.
Cystic Neoplasms:
- Serous Cystadenoma: Generally benign, serous fluid-filled cysts.
- Mucinous Cystic Neoplasms: May be benign or malignant, contain mucinous fluid. Similar types occur in the ovary.
Neuroendocrine Tumors:
- Arise from islet cells, may secrete hormones (e.g., insulinomas).
- Diagnosed by chromogranin staining and measuring blood chromogranin A levels.
- Prognosis varies based on the tumor grade and type.
Premalignant Lesions:
- Pancreatic Intraepithelial Neoplasia (PanIN): Precursor to ductal adenocarcinoma.
- Intraductal Papillary Mucinous Neoplasm (IPMN): Mucin-producing, can progress to malignancy.
Gallbladder Pathology - Types of Diseases
Gallstones:
- Cholesterol Stones: Contain >50% cholesterol, usually single and radiolucent.
- Pigment Stones: Contain bilirubin, often multiple and radiopaque.
- Mixed Stones: Characteristics of both types.
- Risk Factors: Female gender, obesity, rapid weight loss, genetic predisposition.
Acute Cholecystitis:
- Inflammation due to gallstone obstruction.
- Presents with severe abdominal pain, fever, leukocytosis.
- Histology: Acute inflammation, edema, possible necrosis.
Chronic Cholecystitis:
- Recurrent episodes of inflammation, often associated with gallstones.
- Gallbladder wall becomes thickened and fibrotic.
- Rokitansky-Aschoff Sinuses: Herniations of the mucosa into the muscularis layer.
Gallbladder Cancer:
- Rare but highly aggressive adenocarcinoma.
- Strongly associated with chronic inflammation and gallstones.
- Presents late with poor prognosis.
- Histology: Gland-forming, mucin-secreting carcinoma.
Summary
Pancreatic Diseases: Focus on acute and chronic pancreatitis, including their causes, pathogenesis, histological features, and complications. Also covers pancreatic neoplasms and their types, risk factors, and prognostic indicators.
Gallbladder Diseases: Discussion on gallstones, acute and chronic cholecystitis, and gallbladder cancer. Emphasizes the importance of recognizing the histological and clinical features of each condition.
Importance: Understanding the pathology of the pancreas and gallbladder is crucial for accurate diagnosis, management, and treatment of these conditions.
Future Directions: Continued research on the genetic and molecular mechanisms of these diseases, development of targeted therapies, and improvement in diagnostic techniques.
