Common surgical pathologies of the liver, pancreas and biliary tract

Definition / Overview

• The hepatopancreaticobiliary (HPB) system encompasses a broad range of benign and malignant conditions that demand a structured diagnostic and operative framework.
• For the FRACS candidate, mastery of this domain requires integration of anatomy, pathophysiology, staging, and multidisciplinary decision-making.
• This note organises conditions by organ system, emphasising the clinical features, investigation strategy, operative principles, and complications most likely to appear in viva and SAQ formats.

Hepatic Pathology

Benign Liver Lesions

• The widespread use of cross-sectional imaging has dramatically increased the incidental detection of liver lesions.
• A systematic approach, patient demographics, lesion characteristics, and clinical context, allows definitive diagnosis in most cases without tissue biopsy.

• Key operative principle for HCA: Resect lesions >5 cm or those in women wishing to continue pregnancy, given risk of rupture and haemorrhage.
• All HCAs should have OCP or androgen therapy ceased, with interval imaging to assess regression.

Hepatocellular Carcinoma (HCC)

• Epidemiology: Most common primary liver malignancy; strongly associated with cirrhosis (hepatitis B/C, alcohol, NAFLD/NASH, haemochromatosis).
• Pathophysiology: Arises via chronic inflammation → fibrosis → cirrhotic nodule → dysplastic nodule → HCC. Non-cirrhotic HCC occurs but is less common.
• Staging: Barcelona Clinic Liver Cancer (BCLC) system is the preferred framework; integrates tumour burden, liver function (Child-Pugh/MELD), and performance status.

• Milan criteria for transplant: Single lesion ≤5 cm, or ≤3 lesions each ≤3 cm, no macrovascular invasion, no extrahepatic disease.
• Surveillance: 6-monthly ultrasound ± AFP in cirrhotic patients.
• Fibrolamellar variant: Young patients without underlying liver disease; better resectability and improved survival.

Colorectal Liver Metastases (CRLM)

• Commonest hepatic malignancy in Western countries.
• Resectability defined by ability to achieve $R_0$ resection with adequate future liver remnant (FLR ≥20% in normal liver; ≥30-40% post-chemotherapy or in chronic liver disease).
• Strategies to increase resectability: Portal vein embolisation (PVE), associating liver partition with portal vein ligation for staged hepatectomy (ALPPS), staged resections, or systemic chemotherapy downstaging (FOLFOX, FOLFIRI ± bevacizumab/cetuximab).
• Perioperative chemotherapy: Evidence supports perioperative FOLFOX in resectable CRLM, improving progression-free survival.
• Parenchymal-sparing resections are associated with lower morbidity and equivalent oncological outcomes for bilobar disease.

Intrahepatic Cholangiocarcinoma (iCCA)

• Adenocarcinoma arising from intrahepatic bile duct epithelium; incidence is rising.
• Often presents late; symptoms include weight loss, right upper quadrant pain, jaundice (if hilar involvement).
• CA 19-9 and CEA elevated; diagnosis confirmed on imaging ± biopsy.
• Primary treatment is surgical resection with clear margins; lymphadenectomy recommended.
• Adjuvant capecitabine improves survival in resected biliary tract cancers (BILCAP trial).

Biliary Tract Pathology

Cholelithiasis and Choledocholithiasis

• Gallstones: Cholesterol (most common in Western countries), pigment, or mixed. Risk factors: female sex, obesity, rapid weight loss, haemolytic anaemia.
• Choledocholithiasis: Common bile duct stones; present with biliary colic, obstructive jaundice, or complicated cholangitis/pancreatitis.
• Investigation: LFTs, bilirubin, ALP/GGT elevation; ultrasound first-line; MRCP gold standard for non-invasive CBD assessment; ERCP is therapeutic.
• Management: Laparoscopic cholecystectomy with intraoperative cholangiogram (IOC). CBD stones managed by ERCP pre- or post-operatively, or laparoscopic CBD exploration (LCBDE) at time of cholecystectomy.

Acute Cholecystitis

• Obstruction of cystic duct by calculus → distension → secondary bacterial infection.
• Tokyo Guidelines (TG18) grade severity (I-III) and guide timing of cholecystectomy.
• Preferred approach: Early laparoscopic cholecystectomy within 72 hours of symptom onset; safe and reduces total hospital stay.
• Difficult cholecystectomy: Convert to open, use the Critical View of Safety (CVS), consider subtotal cholecystectomy ("fenestrating" technique) when severe inflammation precludes safe dissection at Calot's triangle.

Acute Cholangitis

• Charcot's triad: Fever, jaundice, right upper quadrant pain. Addition of hypotension and altered consciousness = Reynolds' pentad (septic/suppurative cholangitis, high mortality).
• Causes: Choledocholithiasis (40-70%), malignancy (10-60%), benign stricture (5-30%), post-instrumentation.
• Grading: TG18 mild (Grade I), moderate (Grade II), severe (Grade III).
• Management:

1. IV fluid resuscitation and broad-spectrum antibiotics (gram-negative and anaerobic cover)
2. Biliary decompression, ERCP is first-line; percutaneous transhepatic cholangiography (PTC) if ERCP fails or anatomy precludes access
3. Surgical decompression reserved for failed endoscopic/percutaneous approaches
4. Treat underlying cause (stone extraction, stricture management) after patient stabilised

Cholangiocarcinoma (Extrahepatic)

• Perihilar (Klatskin tumour): Most common extrahepatic CCA; arises at hepatic duct bifurcation. Classified by Bismuth-Corlette system.
• Distal CCA: Arises in the CBD below the cystic duct confluence; treated by Whipple procedure.

• Resectability determined by vascular involvement (portal vein, hepatic artery), contralateral lobe atrophy, and FLR adequacy.
• Adjuvant capecitabine recommended post-resection.
• Advanced/unresectable disease: gemcitabine + cisplatin ± durvalumab.

Choledochal Cysts

• Congenital cystic dilatation of the biliary tree; classified by Todani system (Type I most common, fusiform dilatation of CBD).
• Risk of malignancy increases with age if untreated; reflux of pancreatic enzymes (anomalous pancreaticobiliary junction) drives mucosal damage and carcinogenesis.
• Treatment: Complete cyst excision with biliary-enteric reconstruction (Roux-en-Y hepaticojejunostomy); cholecystectomy included.
• Long-term surveillance required even post-excision: cholangitis, intrahepatic stones, anastomotic stricture, and residual malignant risk.

Benign Biliary Strictures

• Causes include iatrogenic bile duct injury (most common, post-cholecystectomy), primary sclerosing cholangitis (PSC), chronic pancreatitis, post-anastomotic stricture, and ischaemic cholangiopathy.
• Consequence of untreated stricture: recurrent cholangitis, secondary biliary cirrhosis, portal hypertension, and liver failure.
• Management: ERCP with balloon dilatation and stenting (first-line for short strictures); surgical hepaticojejunostomy for failed endoscopic management or complex injuries (Strasberg E injuries).

Primary Sclerosing Cholangitis (PSC)

• Progressive fibro-inflammatory stricturing of intra- and extrahepatic ducts; strongly associated with ulcerative colitis.
• Risk of cholangiocarcinoma (lifetime risk ~10-15%), gallbladder cancer, and colorectal cancer.
• Ultimately leads to biliary cirrhosis; liver transplantation is definitive management.

Pancreatic Pathology

Acute Pancreatitis

• Causes: Gallstones (most common), alcohol, hypertriglyceridaemia, medications, post-ERCP, idiopathic.
• Pathophysiology: Premature activation of pancreatic enzymes → auto-digestion → local and systemic inflammatory response.
• Severity: Revised Atlanta Classification, mild, moderately severe (local complications or transient organ failure <48 h), or severe (persistent organ failure).
• Scoring: APACHE II, Ranson's criteria, BISAP; CT severity index (CTSI) for morphological staging.
• Management of severe AP:

1. Aggressive IV fluid resuscitation (Hartmann's/Ringer's lactate preferred over normal saline)
2. Analgesia, bowel rest; early enteral nutrition via nasojejunal tube preferred over parenteral nutrition
3. Antibiotics only if proven infected necrosis (not prophylactic)
4. ERCP within 24 hours if concurrent cholangitis; within 72 hours for persisting biliary obstruction
5. Intervention for infected pancreatic necrosis: step-up approach (percutaneous drain → minimally invasive necrosectomy → open if required)

• Biliary pancreatitis: Cholecystectomy during index admission (mild disease) or after clinical resolution (severe disease) to prevent recurrence.

Chronic Pancreatitis

• Irreversible inflammatory fibrosis of the pancreas; commonest cause is alcohol.
• Features: exocrine insufficiency (steatorrhoea), endocrine insufficiency (diabetes), chronic pain, ductal strictures with upstream dilatation, pseudocysts.
• Surgical indications: Intractable pain, ductal obstruction, suspicion of malignancy, biliary obstruction.
• Operations:
  • Dilated duct (≥5 mm): Lateral pancreaticojejunostomy (Puestow / Partington-Rochelle)
  • Head-dominant disease: Frey procedure (local head excision + lateral pancreaticojejunostomy) or Beger procedure (duodenum-preserving head resection)
  • Diffuse disease: Total pancreatectomy ± islet autotransplantation

Pancreatic Adenocarcinoma (PDAC)

• 85% of pancreatic malignancies; majority arise in the head of the gland.
• Typically presents late: painless obstructive jaundice (head lesions), weight loss, new-onset diabetes.
• Staging: CT pancreas protocol (dual-phase) is cornerstone. Classified by relationship to superior mesenteric artery (SMA) and vein (SMV), portal vein (PV), and coeliac axis.

• Operative approaches:
  • Head/uncinate: Pancreaticoduodenectomy (Whipple); pylorus-preserving variant equivalent oncologically
  • Body/tail: Distal pancreatectomy + splenectomy; minimally invasive approach increasingly used
• Perioperative management: Biliary stenting pre-operatively only if surgery delayed >2 weeks or cholangitis present.
• Neoadjuvant therapy: Standard for borderline resectable disease (FOLFIRINOX or gemcitabine-nab-paclitaxel); growing evidence for use in resectable disease.
• Adjuvant therapy: Modified FOLFIRINOX preferred post-resection if performance status allows; gemcitabine + capecitabine is an alternative.
• Prognosis: 5-year survival $\approx 20-25\%$ after $R_0$ resection; <5% overall.

Pancreatic Cystic Lesions

Pancreatic Neuroendocrine Tumours (pNETs)

• Functional (insulin-, gastrin-, glucagon-, VIP-secreting) or non-functional (more common, often larger at presentation).
• Insulinoma: Most common functional pNET; Whipple's triad (symptoms with fasting hypoglycaemia, glucose <2.5 mmol/L, relief with glucose); localise with EUS ± $^{68}$Ga-DOTATATE PET-CT; enucleation for small lesions.
• Gastrinoma (Zollinger-Ellison syndrome): Hypersecretion → refractory peptic ulcers + diarrhoea; 60-90% malignant; localise and resect; PPI therapy essential.
• Non-functional pNETs >2 cm: Resect; liver metastases may be amenable to debulking or somatostatin analogues.

Complications & Special Considerations

• Post-hepatectomy liver failure: Bilirubin >50 µmol/L + INR >1.5 on post-operative day 5 (International Study Group of Liver Surgery definition). Prevention: adequate FLR, optimal patient selection.
• Bile leak post-hepatectomy or biliary anastomosis: Drain bilirubin $> 3\times$ serum bilirubin on day 3+; manage with drainage ± ERCP stenting; reoperation rarely required.
• Post-pancreatectomy haemorrhage (PPH): Can be early (operative bed) or delayed (sentinel bleed from pseudoaneurysm); CT angiography and interventional radiology embolisation is first-line for haemodynamically stable patients.
• Postoperative pancreatic fistula (POPF): Biochemical leak (Grade A) requires no change in management; Grade B requires prolonged drain or percutaneous drainage; Grade C requires reoperation.
• Delayed gastric emptying (DGE): Common post-Whipple; managed conservatively with prokinetics and nutritional support.

Perioperative Management

• Nutritional optimisation: Prehabilitation and early enteral feeding post-operatively; total pancreatectomy patients require enzyme replacement and insulin therapy indefinitely.
• DVT prophylaxis: LMWH commenced within 12-24 hours post-operatively; extended prophylaxis (28 days) for oncological HPB resections given high VTE risk; combine with mechanical compression.
• Enhanced Recovery After Surgery (ERAS): Multimodal analgesia (epidural or intrathecal opioid + wound infiltration + NSAIDs), early oral intake, minimisation of IV fluids, and early mobilisation improve outcomes across HPB procedures.
• MDT decision-making: All HPB malignancies should be discussed at a multidisciplinary tumour board incorporating HPB surgery, medical and radiation oncology, interventional radiology, gastroenterology, and pathology prior to definitive management.
• Jaundice work-up prior to HPB surgery: Structured approach, LFTs, bilirubin fractionation, tumour markers (CA 19-9, AFP, CEA), ultrasound, CT (triple-phase), MRCP/EUS; biopsy only when diagnosis will change management and patient is not proceeding directly to resection.