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Surgical Diseases of the Liver and Pancreas

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PART I: THE LIVER

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LO1 - Surgical Anatomy and Main Functions of the Liver

Gross and Segmental Anatomy

• Falciform ligament - connects the liver to the anterior abdominal wall and carries the ligamentum teres (obliterated left umbilical vein)
• Coronary ligaments - form the boundaries of the bare area (where the liver is in direct contact with the diaphragm)
• Left and right triangular ligaments - lateral extensions of the coronary ligaments
• Hepatoduodenal ligament - the free edge of the lesser omentum, carrying the portal triad: portal vein, hepatic artery, and common bile duct (the porta hepatis or hepatic hilum)

Couinaud Segmental Classification

• Portal venous branch
• Hepatic arterial branch
• Biliary drainage
• Hepatic venous outflow

• Segment I: Caudate lobe (posterior, drains directly into IVC)
• Segments II, III: Left lateral section (left of falciform ligament)
• Segment IV (IVa, IVb): Left medial section (quadrate lobe)
• Segments V, VI: Right lobe inferior
• Segments VII, VIII: Right lobe superior

"There are two anatomical lobes with a separate blood supply, bile duct and venous drainage... Resection is based on anatomical lines to preserve maximal functioning liver and blood supply." - BL, p. 1512

Blood Supply - Dual Hepatic Circulation

• Portal vein (80% of hepatic blood flow, ~60% of oxygen): carries nutrient-rich blood from the gut and spleen
• Hepatic artery (20% of flow, ~40% of oxygen): branch of the celiac axis, carries oxygenated blood

Ligament of Pringle / Hepatoduodenal Ligament

Main Functions of the Liver

Regeneration

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LO2 - Common Clinical Presentations of Liver Disease

Jaundice

Hepatomegaly

• Congestive cardiac failure (tender, pulsatile in tricuspid regurgitation)
• Hepatitis (viral, alcoholic - tender)
• Cirrhosis (initially enlarged, later shrunken)
• Primary or secondary liver tumours (irregular, hard surface)
• Hepatic cysts, abscesses
• Infiltrative disorders (fatty liver, amyloidosis)

Right Upper Quadrant (RUQ) Pain

• Acute hepatitis - dull RUQ ache with tender hepatomegaly
• Liver abscess - severe RUQ pain with swinging fever
• Biliary colic - severe, colicky RUQ/epigastric pain radiating to right shoulder (from gallstones)
• Liver tumours - dragging/aching pain from capsular distension

Other Clinical Signs and Symptoms

• Spider naevi (>5 is pathological)
• Palmar erythema
• Leukonychia (white nails)
• Clubbing
• Dupuytren's contracture
• Gynaecomastia, testicular atrophy (in alcohol-related disease)
• Caput medusae (distended periumbilical veins - portal hypertension)
• Ascites (shifting dullness, fluid thrill)
• Peripheral oedema
• Splenomegaly (portal hypertension)
• Flapping tremor / asterixis (hepatic encephalopathy)

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LO3 - Laboratory and Imaging Investigations for Liver Disease

Laboratory Investigations

• Full Blood Count (FBC): anaemia (chronic disease/haemolysis), thrombocytopenia (portal hypertension), macrocytosis (alcohol)
• Hepatitis serology: HBsAg, anti-HCV, anti-HAV, anti-HEV
• Auto-antibodies: ANA, ASMA (autoimmune hepatitis); AMA (primary biliary cholangitis)
• Ferritin, transferrin saturation: haemochromatosis
• Caeruloplasmin, serum copper: Wilson's disease
• Alpha-fetoprotein (AFP): hepatocellular carcinoma (HCC) tumour marker
• CEA, CA 19-9: metastatic disease surveillance

Imaging Investigations

• First-line imaging modality for the liver
• Inexpensive, no radiation, widely available
• Excellent for: biliary pathology (gallstones, duct dilatation), focal liver lesions, ascites, portal vein assessment with Doppler
• Limitations: operator-dependent, poor visualisation through ribs or bowel gas, obesity
• Contrast-enhanced US (CEUS) improves lesion characterisation

"Ultrasonography is a useful initial imaging test of the liver because it is inexpensive, widely available, involves no radiation exposure, and is well tolerated by patients. It is excellent for diagnosing biliary pathology and focal liver lesions." - SPS, p. 1383

• Triple-phase CT (non-contrast, arterial, portal venous): gold standard for characterising focal liver lesions
• HCC: arterial enhancement with "washout" in portal phase
• Liver metastases: typically hypodense on portal phase
• Assesses liver volume, vascular anatomy, and extrahepatic disease
• Excellent for biliary anatomy and staging of malignancy

• Superior soft tissue resolution
• MRI with hepatocyte-specific contrast (e.g. Primovist/gadoxetate): excellent for characterising small lesions, detecting metastases, differentiating HCC from regenerative nodules
• MRCP (Magnetic Resonance Cholangiopancreatography): non-invasive, no radiation, excellent visualisation of biliary tree and pancreatic duct - the investigation of choice for suspected biliary obstruction
• MR Elastography: assesses liver stiffness/fibrosis non-invasively

"MRCP provides visualisation of dilated bile ducts, and the high spatial and contrast resolution often enables accurate assessment of the level of occlusion in the biliary tree." - SPS, p. 1387

• Functional imaging using FDG (18F-fluorodeoxyglucose)
• Used for staging malignancy, detecting occult metastases, and confirming lymph node involvement
• FDG uptake correlates with metabolic activity - high-grade HCC is PET-avid, low-grade HCC may be PET-cold
• BL, p. 1857-1861; SPS, p. 1385-1387

• ERCP (Endoscopic Retrograde Cholangiopancreatography): diagnostic and therapeutic for biliary obstruction; allows stenting, stone extraction, biopsy
• PTC (Percutaneous Transhepatic Cholangiography): when ERCP is not possible; allows biliary drainage
• Liver Biopsy: for histological diagnosis of parenchymal disease; guided by US or CT
• Laparoscopy + Laparoscopic Ultrasonography: staging of HPB cancers, detects peritoneal metastases, avoids unnecessary laparotomy
• Angiography: for therapeutic embolisation, TACE (transarterial chemoembolisation)
• Octreotide scan (Scintigraphy): for somatostatin receptor-positive neuroendocrine tumours

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LO4 - Causes and Differential Diagnoses of Jaundice

"Workup of a patient with jaundice is simplified by organizing the possible causes of the disorder into groups based on the location of bilirubin metabolism... prehepatic, intrahepatic, and posthepatic." - SPS, p. 1381

Prehepatic Jaundice (Unconjugated Hyperbilirubinaemia)

• Haemolytic anaemia: hereditary spherocytosis, sickle cell disease, G6PD deficiency, thalassaemia
• Acquired haemolysis: autoimmune haemolytic anaemia (Coombs test positive), microangiopathic haemolytic anaemia, drug-induced, transfusion reactions
• Ineffective erythropoiesis: megaloblastic anaemia
• Impaired albumin transport: severe malnutrition, burns (reduced carrier protein)
• Gilbert's syndrome: benign, common (~4-7% of population); reduced glucuronyltransferase activity causing mild unconjugated hyperbilirubinaemia during fasting or stress
• Crigler-Najjar syndrome: rare neonatal condition; severe absence of glucuronyltransferase; can cause bilirubin encephalopathy

Intrahepatic Jaundice (Medical / Hepatocellular Causes)

• Viral hepatitis: Hepatitis A, B, C, D, E
• Alcoholic hepatitis
• Drug-induced liver injury (DILI): paracetamol (acetaminophen) overdose, halothane, isoniazid-rifampicin, NSAIDs, antibiotics, antidepressants, valproic acid
• Autoimmune hepatitis
• Cirrhosis (any cause: alcohol, viral, metabolic, autoimmune)
• Non-alcoholic fatty liver disease (NAFLD/NASH)
• Ischaemic hepatitis ("shock liver"): from any cause of reduced hepatic perfusion
• Sepsis
• Intrahepatic cholestasis: primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC), drugs
• Hereditary excretion defects: Dubin-Johnson syndrome, Rotor's syndrome (impaired secretion of conjugated bilirubin)
• Pregnancy-related: intrahepatic cholestasis of pregnancy
• Wilson's disease, haemochromatosis, alpha-1 antitrypsin deficiency

Posthepatic (Obstructive) Jaundice - SURGICAL Causes

• Choledocholithiasis (common bile duct stones) - most common surgical cause
• Blood clot (haemobilia)
• Parasites (Ascaris, Clonorchis)

• Bile duct strictures: benign post-surgical (post-cholecystectomy), post-inflammatory (PSC, chronic pancreatitis)
• Cholangiocarcinoma (bile duct cancer): can be intrahepatic, perihilar (Klatskin tumour - most common), or distal
• Ampullary carcinoma

• Carcinoma of the head of pancreas - the most common cause of painless progressive obstructive jaundice in the elderly; "Courvoisier's law" - if a palpable, non-tender gallbladder accompanies jaundice, the cause is unlikely to be gallstones (as chronic gallstone disease scars the gallbladder wall, preventing distension)
• Enlarged lymph nodes at the porta hepatis (lymphoma, metastases - Mirizzi syndrome can mimic this)
• Pancreatitis (head oedema compressing distal bile duct)
• Hepatic metastases / HCC compressing intrahepatic ducts

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LO5 - Interpreting Investigations: Medical vs Surgical Causes of Liver Disease

Step 1 - History clues

• Surgical: painless progressive jaundice + weight loss (pancreatic cancer); colicky RUQ pain + fever + jaundice (Charcot's triad of cholangitis from choledocholithiasis); palpable gallbladder (Courvoisier's sign)
• Medical: viral prodrome, contacts, IV drug use, alcohol history, medications, autoimmune features

Step 2 - LFT pattern

• Obstructive pattern: ALP disproportionately elevated (e.g. ALP 600 IU/L, ALT 80 IU/L); conjugated bilirubin predominates; prolonged PT may occur late
• Hepatocellular pattern: ALT/AST disproportionately elevated (e.g. ALT 1200 IU/L, ALP 150 IU/L); both conjugated and unconjugated bilirubin elevated; PT may be significantly prolonged early

Step 3 - Bilirubin fractionation

• Predominantly conjugated (direct) bilirubin = hepatocellular or obstructive (requires further differentiation by imaging)
• Predominantly unconjugated (indirect) bilirubin = prehepatic or defective conjugation

Step 4 - Ultrasound

• Dilated intra- or extrahepatic bile ducts = obstructive/surgical cause until proven otherwise
• Common bile duct (CBD) >8 mm diameter is abnormal (>10 mm post-cholecystectomy)
• May reveal the cause: gallstones in CBD, pancreatic mass, liver lesion
• No duct dilatation = medical/hepatocellular cause more likely (biopsy if indicated)

Step 5 - Further imaging

• CT/MRCP: define the level and cause of obstruction; assess resectability
• ERCP: if therapeutic intervention needed (stenting, stone extraction)

Summary Algorithm

Jaundice
  ├── Unconjugated bilirubin dominant → Prehepatic (haemolysis, Gilbert's)
  └── Conjugated bilirubin dominant
        ├── ALT/AST markedly raised → Hepatocellular (hepatitis, DILI)
        ├── ALP markedly raised → Obstructive
        │     └── Ultrasound → Dilated ducts?
        │           ├── YES → SURGICAL cause → CT/MRCP → define level and cause
        │           └── NO → Intrahepatic cholestasis (PBC, PSC, drugs) → Biopsy

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PART II: THE PANCREAS

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LO6 - Anatomy and Main Functions of the Pancreas

Gross Anatomy

• Head: lies in the C-loop of the duodenum; the uncinate process is a downward and medial projection behind the superior mesenteric vessels
• Neck: lies directly over the superior mesenteric vein (SMV) and portal vein confluence - important surgical landmark
• Body: crosses the spine; the splenic vein runs along its posterior surface
• Tail: extends to the hilum of the spleen; lies within the splenorenal ligament

Ductal Anatomy

• Main pancreatic duct (duct of Wirsung): runs the entire length of the pancreas and joins the common bile duct to form the ampulla of Vater (hepatopancreatic ampulla), which opens into the second part of the duodenum at the major papilla. Controlled by the sphincter of Oddi
• Accessory duct (duct of Santorini): drains the upper head and opens separately at the minor papilla (2 cm proximal to major papilla)
• Pancreas divisum: failure of fusion of ventral and dorsal pancreatic ducts (5-10% of population); can cause recurrent pancreatitis

Relations and Surgical Importance

• Anterior: lesser sac (epiploic foramen gives access)
• Posterior: aorta, IVC, left renal vein, both adrenals, splenic vein, superior mesenteric vessels
• The bile duct passes through or posterior to the head of the pancreas - pancreatic head pathology commonly causes obstructive jaundice
• The duodenum shares a blood supply with the pancreatic head (pancreaticoduodenal arteries) - hence they are resected together in a Whipple procedure

Blood Supply

• Pancreatic head: superior and inferior pancreaticoduodenal arteries (from gastroduodenal artery and SMA respectively)
• Body and tail: splenic artery branches (dorsal pancreatic, great pancreatic artery)
• Venous drainage is to the portal vein via splenic and SMV

Functions of the Pancreas

• Produces 1-2 litres/day of pancreatic juice (pH 8.0-8.3, rich in bicarbonate from ductal cells)
• Digestive enzymes (secreted as inactive zymogens to prevent autodigestion):
  • Proteases: trypsinogen (activated by enterokinase in duodenum to trypsin), chymotrypsinogen, proelastase, procarboxypeptidase
  • Lipase and colipase: fat digestion
  • Amylase: starch digestion
  • Phospholipase A2, DNase, RNase
• Regulated by: secretin (stimulates bicarbonate), cholecystokinin (CCK) (stimulates enzyme secretion)

• Beta (β) cells (70%): insulin - lowers blood glucose
• Alpha (α) cells (20%): glucagon - raises blood glucose
• Delta (δ) cells: somatostatin - inhibits insulin and glucagon
• PP cells: pancreatic polypeptide

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LO7 - Common Clinical Features of Pancreatic Disease

Acute Pancreatitis

"The underlying mechanism of injury in pancreatitis is thought to be premature activation of pancreatic enzymes within the pancreas, leading to a process of autodigestion." - BL, p. 7597

• Gallstones (most common in UK/Ireland - 40-50%)
• Ethanol/alcohol (30-35%)
• Trauma
• Steroids
• Mumps (and other viral infections)
• Autoimmune (IgG4-related)
• Scorpion venom
• Hyperlipidaemia / Hypercalcaemia
• ERCP (post-procedural)
• Drugs (azathioprine, thiazides, furosemide, oestrogens, tetracyclines)

• Pain: severe, constant epigastric/upper abdominal pain, radiating to the back; may be relieved by sitting forward; builds over minutes to hours
• Nausea and vomiting
• Fever (low-grade early; high fever suggests secondary infection/cholangitis)
• Tachycardia, hypotension (in severe disease - systemic inflammatory response)
• Abdominal tenderness: epigastric, often with guarding; periumbilical bruising (Cullen's sign) and flank bruising (Grey Turner's sign) - indicate retroperitoneal haemorrhage, appear 24-48 hours after onset
• Ileus - absent bowel sounds, abdominal distension
• Jaundice - if gallstone impacted at ampulla or oedema of head compressing CBD
• Respiratory: basal crackles, pleural effusion (especially left-sided), in severe disease - ARDS

• Mild (interstitial oedematous pancreatitis): most cases (80%); no organ failure, no necrosis; mortality <1%
• Moderate: transient organ failure (<48 hrs) or local complications
• Severe (necrotising pancreatitis): persistent organ failure (>48 hrs) and/or infected necrosis; mortality 15-30%

• Ranson's criteria (11 parameters at admission and 48 hours)
• APACHE II score
• Glasgow/Imrie criteria (8 parameters at 48 hours) - score ≥3 indicates severe attack
• CT Severity Index (Balthazar score): grades A-E based on CT findings of necrosis and fluid collections; used after 72 hours

Chronic Pancreatitis

• Pain: recurrent or persistent epigastric pain radiating to the back - the dominant symptom
• Exocrine insufficiency: steatorrhoea (pale, fatty, offensive stools, floating), malabsorption, weight loss - occurs when >90% of acinar function is lost
• Endocrine insufficiency: diabetes mellitus ("pancreatogenic diabetes") - occurs late
• Obstructive jaundice: from fibrosis of the head of pancreas compressing the bile duct
• Duodenal obstruction: from fibrosis in the pancreatic head
• Pancreatic pseudocyst formation

Pancreatic Masses

• Painless, progressive obstructive jaundice (head of pancreas cancer pressing on CBD) - classic presentation; Courvoisier's gallbladder may be palpable
• Epigastric/back pain: visceral pain from retroperitoneal invasion; often described as a boring, persistent ache; worse at night; improved by sitting forward
• Weight loss and cachexia: from malabsorption and systemic tumour effects
• New-onset diabetes mellitus in an older patient (destruction of islets; or paraneoplastic effect)
• Steatorrhoea: from pancreatic duct obstruction
• Trousseau's syndrome: migratory thrombophlebitis (venous thrombosis) associated with pancreatic adenocarcinoma
• Palpable epigastric mass: usually advanced disease
• Gastric outlet obstruction: duodenal invasion by head of pancreas tumour

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LO8 - Laboratory and Imaging Investigations for Pancreatic Disease

Laboratory Investigations

• CA 19-9 (carbohydrate antigen 19-9): tumour marker for pancreatic adenocarcinoma; elevated in ~80% of cases; not diagnostic alone (elevated in benign biliary disease too); useful for monitoring treatment response and recurrence
• CEA: less specific
• Faecal elastase-1: marker of exocrine insufficiency (<200 µg/g stool = significant insufficiency)
• 72-hour faecal fat test: gold standard for malabsorption but rarely used clinically
• HbA1c, fasting glucose: assess endocrine insufficiency
• IgG4 levels: elevated in autoimmune pancreatitis
• PRSS1, SPINK1, CFTR genetic testing: if hereditary pancreatitis suspected

Imaging Investigations

• First-line for suspected pancreatitis
• Detects gallstones (cause of pancreatitis) - sensitivity >95% for gallbladder stones but poor for CBD stones
• Detects pancreatic oedema, peripancreatic fluid
• Detects masses, duct dilatation, and vascular involvement (with Doppler)
• Often limited by overlying bowel gas

• Gold standard for:
  • Confirming diagnosis when in doubt
  • Assessing severity of acute pancreatitis (Balthazar scoring/CT Severity Index) - best performed 72 hours after onset to allow full evolution of necrosis
  • Detecting and characterising pancreatic masses
  • Staging pancreatic cancer (assessing vascular involvement, metastases, resectability)
  • Detecting complications (pseudocysts, vascular complications, abscesses)
• BL, p. 1691: "CT remains the mainstay of accurate diagnosis"

• Superior to CT for soft tissue characterisation of pancreatic lesions
• MRCP: non-invasive ductal imaging - excellent for pancreatic duct changes in chronic pancreatitis (irregular "chain of lakes" appearance), ductal stones, ampullary pathology
• Better than CT for detecting small liver metastases
• Essential for evaluating cystic pancreatic lesions (IPMN, MCN vs pseudocyst)

• Highly sensitive (>90%) for pancreatic masses, especially lesions <2 cm
• Allows fine needle aspiration (FNA)/biopsy for histological diagnosis
• Best modality for staging local vascular invasion (portal vein, SMA, SMV)
• Used to evaluate cystic lesions and obtain fluid for CEA, amylase, and cytology
• Detects CBD stones with high sensitivity (better than CT/US)

• Diagnostic and therapeutic for biliary and pancreatic ductal pathology
• Detects CBD stones, allows stenting of biliary obstruction (e.g. cancer, strictures)
• "Chain of lakes" appearance in main duct of chronic pancreatitis
• Thick mucus extruding from ampulla is diagnostic of main duct IPMN
• Carries risk of post-ERCP pancreatitis (2-5%)
• Largely replaced for diagnosis by MRCP; retained for therapy

• For staging of pancreatic cancer, detecting distant metastases
• Differentiating between autoimmune pancreatitis (which can mimic cancer) and malignancy

• Staging of pancreatic cancer prior to laparotomy - detects small peritoneal metastases and liver metastases not seen on CT

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LO9 - Differential Diagnoses of Pancreatic Pathology

For Epigastric Pain / Acute Abdominal Presentation:

1. Acute pancreatitis (gallstones, alcohol) - most common
2. Peptic ulcer disease (duodenal/gastric ulcer) or perforation
3. Biliary colic / cholecystitis / cholangitis
4. Acute mesenteric ischaemia
5. Perforated hollow viscus
6. Aortic aneurysm (ruptured or dissection)
7. Inferior myocardial infarction (can mimic epigastric pain)
8. Pancreatitis from other causes (post-ERCP, drug-induced, hypercalcaemia)

For Chronic Pancreatic Pain:

1. Chronic pancreatitis (alcohol, idiopathic, hereditary)
2. Pancreatic cancer (must always be excluded)
3. Autoimmune pancreatitis (IgG4)
4. Pancreatic pseudocyst
5. Peptic ulcer disease
6. Functional dyspepsia / irritable bowel syndrome

For Painless Obstructive Jaundice + Weight Loss:

1. Carcinoma of the head of the pancreas (most important to exclude)
2. Cholangiocarcinoma (distal CBD / Klatskin tumour)
3. Ampullary carcinoma (periampullary cancer)
4. Duodenal carcinoma
5. Autoimmune pancreatitis (mimics cancer on imaging)
6. Sclerosing cholangitis (PSC)
7. Chronic pancreatitis (inflammatory head mass)
8. Choledocholithiasis (CBD stones - usually associated with pain/cholangitis)
9. Metastatic lymphadenopathy at the hepatoduodenal ligament
10. Lymphoma

For Pancreatic Cystic Lesion on Imaging:

1. Pseudocyst (most common; post-pancreatitis; high amylase in cyst fluid, low CEA)
2. Serous cystadenoma (benign; older women; multiple small cysts)
3. Mucinous cystic neoplasm (MCN) (premalignant; perimenopausal women; body/tail; ovarian-type stroma; thick-walled)
4. Intraductal papillary mucinous neoplasm (IPMN) (premalignant to malignant; head of pancreas; main duct IPMNs are high risk)
5. Solid pseudopapillary neoplasm (SPN): rare; young women; part-solid, part-cystic
6. Cystic neuroendocrine tumour

"It is important to differentiate a pseudocyst from an APFC... a cystic neoplasm may be confused with a chronic pseudocyst. EUS and aspiration of the cyst fluid are very useful." - BL, p. 8203-8216

"Fluid from a pseudocyst typically has a low CEA level, and levels above 400 ng/mL are suggestive of a mucinous neoplasm." - BL, p. 8211

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LO10 - Benign vs Malignant Pancreatic Conditions

Benign Pancreatic Conditions

• An inflammatory (not neoplastic) condition; the vast majority of cases resolve completely
• Most patients (80%) have mild disease with mortality <1%
• However, severe necrotising pancreatitis carries significant mortality (15-30%)
• Does not progress to cancer (though chronic pancreatitis is a risk factor)

• Irreversible but benign inflammatory/fibrotic condition
• Causes permanent exocrine and endocrine insufficiency
• An independent risk factor for pancreatic adenocarcinoma (but not inevitably malignant)
• Management is medical/endoscopic/surgical symptom control

• A benign fluid collection following pancreatitis or trauma; enclosed by fibrous and granulation tissue (not a true epithelial-lined cyst)
• Typically benign and many resolve spontaneously
• Requires intervention only if symptomatic, large (>6 cm), infected, or to exclude malignancy

• "Multiple small cysts, almost like bubble wrap" - BL, p. 8735
• Benign - almost zero malignant potential
• Typically in older women
• Can be observed safely if asymptomatic and diagnosis is certain

• Benign, steroid-responsive condition caused by IgG4-related disease
• Critically important because it mimics pancreatic cancer on imaging and clinically
• Distinguishing features: diffuse enlargement ("sausage pancreas"), halo sign on CT, elevated serum IgG4, rapid response to steroids, associated with other IgG4-related diseases (cholangitis, sialadenitis)

• Arise from islet cells; include insulinoma, gastrinoma, glucagonoma, VIPoma
• Many are functional (produce hormones causing clinical syndromes)
• Most insulinomas are benign (90%)
• Gastrinomas have higher malignant potential (~60% malignant)

Malignant Pancreatic Conditions

• The most common and most lethal primary pancreatic malignancy (~85% of all pancreatic cancers)
• Arises from ductal cells; most commonly in the head of the pancreas (60-70%)
• Prognosis is very poor: overall 5-year survival <10%; only ~20% of patients are resectable at presentation
• Risk factors: smoking, chronic pancreatitis, diabetes mellitus, obesity, family history, BRCA2/PALB2/ATM gene mutations
• Pathology: dense desmoplastic stroma; early perineural invasion, lymphovascular invasion, and distant metastases
• Tumour markers: CA 19-9 elevated in ~80%; used for monitoring, not diagnosis
• Treatment: surgical resection (Whipple's pancreaticoduodenectomy for head lesions; distal pancreatectomy for body/tail) is the only curative option; adjuvant chemotherapy (FOLFIRINOX, gemcitabine/capecitabine) improves survival

• Mucinous Cystic Neoplasm (MCN): carries significant risk of malignant transformation; all MCNs in fit patients should be resected - BL, p. 8737
• Intraductal Papillary Mucinous Neoplasm (IPMN):
  • Main duct IPMN: high risk of malignancy (~60-70%); resection recommended
  • Branch duct IPMN: lower risk; management depends on size, mural nodules, symptoms
• Pancreatic Intraepithelial Neoplasia (PanIN): microscopic precursor to PDAC (PanIN-1, -2, -3)

• Arises at the ampulla of Vater
• Generally better prognosis than PDAC (5-year survival ~40%) due to earlier presentation (obstructive jaundice when small)
• Treated by Whipple's procedure

• Malignant NETs (e.g. malignant gastrinoma, nonfunctioning NETs) tend to be slow-growing and have far better prognosis than PDAC
• Even with liver metastases, survival can be measured in years with appropriate treatment

Simple Comparison: Benign vs Malignant Pancreatic Conditions

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Summary of Key Points

• The liver has 8 Couinaud segments, each functionally independent, enabling anatomical resection
• Dual blood supply (80% portal, 20% hepatic artery); regenerates to original volume after resection
• Key functions: synthesis (albumin, clotting factors), metabolism (bilirubin, drugs), storage (vitamins, glycogen)
• Clinical presentations: jaundice, hepatomegaly, RUQ pain, ascites, encephalopathy
• Investigations: LFTs pattern (obstructive vs hepatocellular), ultrasound (dilated ducts vs no dilatation), CT/MRCP for level and cause
• Jaundice classification - prehepatic (unconjugated), intrahepatic (mixed), posthepatic/obstructive (conjugated); the last is the surgical cause

• Retroperitoneal organ; head lies in duodenal C-loop; shares blood supply with duodenum
• Exocrine (digestive enzymes, bicarbonate) + endocrine (insulin, glucagon) functions
• Acute pancreatitis: severe epigastric pain, amylase/lipase elevation; causes include gallstones and alcohol
• Pancreatic cancer: painless progressive jaundice, weight loss, back pain; CA 19-9 elevated; poor prognosis
• Investigations: US (first-line), CECT (severity/staging), MRCP (ductal anatomy), EUS-FNA (tissue diagnosis)
• Benign conditions (pancreatitis, pseudocyst, serous cystadenoma) are treatable and non-lethal; malignant (PDAC) has very poor prognosis with <10% 5-year survival

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• Bailey and Love's Short Practice of Surgery, 28th Edition (BL) - Chapters 69, 72 (pp. 1512-1862, 7376-8750)
• Schwartz's Principles of Surgery, 11th Edition (SPS) - Chapter 31 (pp. 1381-1390)
• Sabiston Textbook of Surgery, 21st Edition (SAB) - Chapters on liver and pancreas