Pancreas Pathology (Quiz 3)

UT 402 - Abdomen 2

Endocrine

secreting into blood

Exocrine

secreting into duct

Acini cells

cells of pancreas that perform exocrine functions by secreting digestive enzymes such as amylase and lipase

Amylase

enzyme that aids in digestion of complex carbs

Lipase

enzyme that aids in digestion of fats

Islets of Langerhans

• Cells of the pancreas that perform endocrine function

• Made up of alpha/beta cells

Alpha calls

secrete glucagon

Glucagon

hormone that increases activity of phosphorylase and increases blood sugar

Beta cells

secrete insulin

Insulin

hormone that increases uptake of glucose and amino acids (decreases blood sugar)

Indications for pancreatic US

• Assess for pancreatic malignancy, pancreatitis and its complications  

• Abnormal blood tests

  • Elevated liver function tests (AST, ALT, bilirubin) 

  • Elevated pancreatic enzymes (amylase and lipase) 

• Painless jaundice 

• Suspected acute or chronic pancreatitis 

• Epigastric pain 

• Hx of Gallstones

High amylase

increase indicative of acute pancreatitis

Low amylase

indicative of permanent damage to pancreas, hepatitis, cirrhosis

High lipase

indicative of acute pancreatitis, obstruction of pancreatic duct, and pancreatic carcinoma

High fat excretion (levels of undigested fat in stool)

indicative of pancreatitis

Bilirubin and liver function tests (LFT)

May have abnormal values

Normal Pancreas

• Non-encapsulated 

• Retroperitoneal 

• Located between duodenal loop and splenic hilum

• Size: 

  • Length: 12.5-15 cm

  • Head: 2-3.5 cm

  • Body: 2-3 cm

  • Tail: 1-2 cm

  • Pancreatic Duct/Duct of Wirsung: < 2 mm

US not used to evaluate pancreas for diabetic pts due to nonspecific findings, but there may be …

a slight decrease in pancreas size

Type 1 (AKA insulin-dependent diabetes)

• Autoimmune disease in which insulin-producing cells are destroyed by body’s immune system

• Genetic component, diagnosed early on

• No cure

• Complications: cardiovascular disease, skin issues, gum disease, pregnancy problems, etc. 

Type 2 (AKA insulin-resistant diabetes)

• Metabolic disorder in which body still produces insulin but unable to use effectively

• Diagnosed later in life

• Manageable by diet, exercise, medication

Cystic Fibrosis

• Inherited disorder that damages lungs, digestive system, other organs

• Affects cells that produce mucus, sweat, and digestive juices → decreased enzyme production

  • Mucus becomes thick and sticky

• Can lead to acute/chronic pancreatitis

• Major cause of pancreatic exocrine failure in children

Sonographic appearance of Cystic Fibrosis

• Hyperechoic and small pancreas

  • Hypoechoic areas may be present and represent pancreatic fibrosis 

• Calcifications 

• Small cysts 

• Gallstones and liver disease common

Inflammatory Disease

Pancreas becomes damaged and malfunctions → increased secretion and ducts blocked → pancreatic enzymes digest the pancreas’ own tissues

Acute pancreatitis

• Causes: chronic alcoholism, toxicity from medications, blunt trauma, viral infections, mechanical obstruction of bile ducts (gallstones)

  • Lab results: elevated amylase and lipase

• Symptoms: sudden onset of epigastric pain, fever, malaise, nausea, and vomiting

Acute pancreatitis treatments 

• Aimed at treating symptoms and providing rest for pancreas

  • Surgical removal of gallstones 

  • Alcoholic pancreatitis responds well to quitting alcohol

  • Surgical removal of pancreas only for life-threatening complication

Acute pancreatitis sonographic appearance

• Many cases, pancreas can appear normal

• Diffuse/focal enlargement of pancreas

  • Mainly seen on pancreatic head

  • More reliable indicator of disease

• Hypoechoic compared to chronic pancreatitis

• Pancreatic edema or peripancreatic fluid

• Dilation of pancreatic duct, mainly due to blockage (double barrel sign)

Chronic pancreatitis

• Chronic pancreatitis is acute pancreatitis that lasts > 6 months

  • Due to recurring attacks of acute pancreatitis

• Destruction of pancreatic tissue → atrophy, fibrosis, scarring, calcifications

• Common causes: alcohol-related liver disease, hepatitis B and C, NASH, biliary disease, and autoimmune hepatitis

• Symptoms: persistent epigastric pain, nausea, vomiting, jaundice, 

• Complications: dilated biliary system, pseudocyst formation, venous thrombosis

Sonographic appearance of chronic pancreatitis

• Calcifications 

• Can appear normal, usually more hyperechoic

• Pseudocysts (25-40% of patients)

Pancreatic pseudocysts

• Collection of pancreatic enzymes and bodily fluid in cyst, without epithelial lining

  • Formed from pancreas damage → pancreatic fluid leaks → cyst

• Most common cystic lesions of the pancreas (75-85% of cases)

• Appearance: well-circumscribed, outside pancreas

• Most common symptom: abdominal pain and bloating

Pancreatic pseudocyst rupture

• Requires immediate surgical intervention if causes signs of peritonitis 

• Mortality rate very high without surgical intervention

Fatal complications of chronic pancreatitis

• Pancreatic pseudocyst rupture

• Hemorrhagic pancreatitis

• Phlegmonous pancreatitis

Hemorrhagic pancreatitis

• Rapid progression of acute pancreatitis

• Destruction of parenchyma by pancreatic enzymes

• Causes: alcoholic binge or large meal

• Characteristic: bleeding necrosis and paralysis of digestive tract

  • Focal fat necrosis or extravasated blood may be visualized

• Grey-Turner sign

• High mortality rate

Grey-Turner sign

blood vessel necrosis causes discoloration of the flanks

Phlegmonous pancreatitis

• Inflammation spreads along fascial pathways → localized area of diffuse inflammatory edema of soft tissue → can lead to necrosis or suppuration

• Involves lesser sac, LT anterior pararenal space, or transverse colon

• Sonographic appearance: hypoechoic ill-defined mass

Neoplastic Disease

• Can be solid or cystic 

• Malignant tumors of pancreas = 4^th leading cause of cancer-related deaths in US

  • Early detection uncommon because symptoms start at later stages

• More common in men older than 30

• Risk factors: smoking, high-fat diet, chronic pancreatitis, diabetes, cirrhosis of the liver

Adenocarcinoma

type of cancer that originates in glandular cells, which are cells that produce mucus or other bodily fluids

Pancreatic adenocarcinoma

• Exocrine origin

  • Largest group of pancreatic cancers

  • Accounts for 90% of all pancreatic malignancies

• Most commonly found in head (60-70%)

• One of most lethal of all malignancies

  • Most people are diagnosed when the cancer is already advanced

• Can arise in ampulla of Vater → difficult to visualize

Sonographic appearance of pancreatic adenocarcinoma

• Nonspecific

• Usually ill-defined, poorly marginated, hypoechoic

  • Can be well-defined, solid, and ovoid

• Increased vascularity 

• Diffused through parenchyma so appears as matted mass of tumor

• Obstruction of biliary tract → dilatation of ducts and GB

• Courvoisier GB

• Enlarged lymph nodes in porta hepatitis and near the aorta indicate nodal metastasis

• Inflammation of pancreas is a common result of carcinomatosis

Carcinomatosis

condition where cancer cells spread widely throughout the body, often to the peritoneum

Courvoisier GB

markedly distended and palpable GB

Other Exocrine Lesions

• Benign solid adenoma

  • More common in women

• Cystadenoma

  • More common in women

• Cystadenocarcinoma

• Squamous cell carcinoma

• Adenoacanthoma

Adenoacanthoma

Uncommon variant of exocrine pancreatic neoplasm

Endoscopic Sonography

• Best imaging method for detecting pancreatic masses < 2 cm 

• Aids in biopsy 

• Most sensitive to detecting venous and gastric invasion

Islet Cell Tumors

• Aka pancreatic neuroendocrine tumors (PNET)

• ~7% of pancreatic tumors

• Slower growing than exocrine tumors

• 3 types

  • Insulinomas

  • Gastrinomas

  • Glucagonomas

Insulinomas

• 70% of cases

• Most common functioning islet cell tumor

• Benign, small, well-encapsulated, good vascularity 

• Seen in pts with hyperinsulinism or hypoglycemia

Gastrinomas

• 20% of cases

• Most are malignant

• Multiple

• Extrahepatic 

  • Difficult to locate

Glucagonomas

• 10% of cases

• Solid and very small

  • Size makes difficult to detect on US

• Can be single or multiple

• More common in pancreatic body/tail

Cystic Neoplastic Lesions

• ~10% of all pancreatic neoplasms

• Usually benign (1% of malignant)

• Fluid-filled structure around or within pancreas → most likely pseudocyst

  • Differentiate with lab tests

• 2 groups

  • Benign serous cystadenomas

  • Malignant mucinous cystic adenomas

Benign serous cystadenomas

• Tumor with multiple cysts < 2cm

• Possible calcifications

• Occurs mainly in head

Malignant mucinous cystic adenomas

• AKA cystadenocarcinoma

• Larger cystic areas (> 2 cm)

• Peripheral calcifications

• Large, unilocular, encapsulated masses

• Occurs mainly in tail

• Has good prognosis for pancreatic malignancy

Intraductal Papillary Mucinous Tumor (IPMT)

• Mucinous cystic neoplasm

• Originates from main pancreatic duct or its branches

• Slow-growing, affects men and women, tends to occur in 60s and 70s 

• Can be benign or malignant

Nonneoplastic Cystic Lesions

• Polycystic disease (ADPKD)

• Von Hippel-Lindau Disease

Polycystic disease (ADPKD)

• Characterized by cysts in kidney, liver, and (in 10% of pts) pancreas

• Pts typically have FMHx of PCD or are being evaluated for HTN, renal insufficiency, or pyelonephritis

• Slowly growing and multiplying cysts destroy normal pancreatic tissue

• Pts will succumb to renal failure before pancreas is physiologically affected

Von Hippel-Lindau Disease

• Genetic disorder that involves central nervous system

• Includes adenomas and islet cell tumors

• 65-75% of pts have some form of pancreatic lesion

• Peripheral calcifications possible

Pancreas Transplant

• Surgical intervention to treat insulin-dependent diabetes

• Gives pt healthy pancreas → pt can now produce their own insulin and don’t need to inject it

• Transplanted pancreas seen in pelvis

Annular Pancreas

• Head of pancreas wraps around duodenum → constricts it and blocks/impairs flow of food to intestines

• Usual treatment: surgical bypass of obstructing segment of duodenum