Pancreas Review for ABSITE 2026: Anatomy, Pancreatitis, Tumors, and Adenocarcinoma

Pancreas Anatomy and Variants

• 🩸 The arterial supply to the pancreas is divided into the head (superior/inferior pancreatic arteries), body (greater inferior and dorsal arteries from splenic artery), and tail (gastroomental and caudal pancreatic arteries from splenic artery).
• 🌊 The venous drainage primarily follows the splenic vein, which converges with the SMV behind the pancreatic neck to form the portal vein.
• 🧬 Pancreatic divisum, a congenital variant due to failed fusion of pancreatic ducts, is usually asymptomatic but can cause pancreatitis; diagnosed with MRCP and treated with ERCP with minor papilla synoplasty.

Acute and Chronic Pancreatitis

• 🍺 Acute pancreatitis is most commonly caused by alcohol and gallstones; management involves clearing the duct (ERCP/IOC) and cholecystectomy during the same admission for gallstone pancreatitis.
• ⏳ Pseudocysts are managed expectantly for 6 weeks to 3 months, with intervention considered for those >6 cm or symptomatic; endoscopic stenting may address ductal abnormalities.
• 📊 The Revised Atlanta Classification categorizes fluid collections based on necrosis and timeline: Acute Peripancreatic Fluid Collection (<4 weeks, non-necrotizing), Pseudocyst (>4 weeks, non-necrotizing), Acute Necrotic Collection (<4 weeks, necrotizing), and Walled-off Necrosis (>4 weeks, necrotizing).
• 🦠 Necrotizing pancreatitis requires antibiotics only if infected (fever, leukocytosis, gas in collection); carbapenems are preferred for pancreatic penetration.
• 📉 Chronic pancreatitis causes include long-standing alcohol abuse, biliary disease, autoimmune conditions, or idiopathic; symptoms include persistent pain, weight loss, malabsorption, and diabetes.

Pancreatic Cystic Neoplasms

• 🔬 Serous Cystadenomas are benign, characterized by low CA 19-9 and amylase in cyst fluid, and are resected if symptomatic or >4 cm.
• ⚠️ Mucinous Cystic Neoplasms have malignant potential, with high CA 19-9 and low amylase; all are resected, especially in surgically fit patients.
• 📈 Intraductal Papillary Mucinous Neoplasms (IPMNs) have malignant potential and are classified by duct involvement: Main duct IPMNs (diffuse dilation >5mm, high malignancy risk, require resection), Mixed IPMNs (combination, require resection), and Branch duct IPMNs (lower risk, management based on cyst characteristics and patient fitness).
• 🧐 High-risk stigmata for branch duct IPMN resection include enhancing mural nodules >5mm, main duct dilation >10mm, or obstructive jaundice.

Pancreatic Neuroendocrine Tumors (PNETs)

• 🌟 Non-functional PNETs are most commonly malignant (60-90%), often found in the pancreatic head, and typically asymptomatic until large; resection is the management for local-regional disease.
• 📉 Insulinomas are the most common functional PNETs (90% benign), presenting with Whipple's triad (hypoglycemia, neuroglycopenic symptoms, relief with glucose); diagnosed biochemically and localized with imaging; managed with enucleation for small, benign tumors or formal resection.
• 📈 Gastrinomas are mostly malignant (60-90%), found in the gastrinoma triangle, causing peptic ulcer disease, diarrhea, and weight loss; diagnosed with elevated gastrin levels and confirmed with secretin stimulation test; managed with enucleation or Whipple procedure depending on location.
• 🩸 Glucagonomas are mostly malignant (~90%), located in the tail, causing the 'four Ds' (dermatitis, diabetes, depression, DVT); managed with resection and regional lymphadenectomy.
• 🛑 Somatostatinomas are mostly malignant, found in the head, causing cholecystitis, diabetes, malabsorption; managed with resection and cholecystectomy; enucleation is contraindicated due to high malignant potential.
• 💧 VIPomas are mostly malignant, presenting with WDHA syndrome (watery diarrhea, hypokalemia, achlorhydria); managed with resection and regional lymphadenectomy; enucleation is contraindicated.

Pancreatic Adenocarcinoma

• 🚬 Risk factors include smoking, heavy alcohol use, chronic pancreatitis, obesity, and chemical exposure.
• 💛 Classic presentation is painless jaundice; imaging includes pancreatic protocol CT/MRI, with staging CT of chest/abdomen/pelvis.
• 🩸 Biliary drainage is considered only for significant cholangitis or coagulopathy, with self-expanding metal stents preferred.
• 🔪 Resectability depends on vascular involvement: SMA/celiac artery (no contact for resectable, <180° for borderline), common hepatic artery (no contact for resectable, contact without extension for borderline), portal vein/SMV (<180° for resectable, >180° or reconstructible for borderline).
• 💊 Adjuvant therapy (e.g., FOLFIRINOX) is standard due to high recurrence rates.
• 📍 Distal tumors are treated with distal pancreatectomy and splenectomy; head tumors with pancreaticoduodenectomy (Whipple procedure).
• 🧬 Associated syndromes with PNETs include MEN1; hereditary pancreatitis is linked to the PRSS1 gene.
• 🔬 Biomarkers for pancreatic adenocarcinoma include CA 19-9.