Cystic Lesions of Pancreas

Pancreatic Cysts - First, Rule Out Fakes!

• Pancreatic cysts: Broadly non-neoplastic (e.g., pseudocysts) or neoplastic.
• Pseudocysts: Most common (75-80%). Not true cysts. 📌 Pseudo = False lining.
  • Lack epithelial lining; wall of fibrous/granulation tissue.
  • Caused by pancreatitis, trauma, surgery.
  • Symptoms: Pain, mass effect, or asymptomatic.
  • Complications: Infection, hemorrhage, rupture.
• Key: Differentiate from neoplastic cysts (MCN, SCN, IPMN).

⭐ Pseudocysts are distinguished by the ABSENCE of an epithelial lining, unlike true cysts which possess one.

Serous Cysts - Grandma's Benign Bubbles

• Benign cystic neoplasm, typically in women >60 yrs (📌 "Grandma" lesion).

• Location: Predominantly pancreatic body/tail.

• Gross: Multiloculated, microcystic ("honeycomb" or "spongy" pattern).

  • Often has a central, stellate fibrous scar (may show calcification).

• Microscopy: Cysts lined by clear, cuboidal, glycogen-rich epithelial cells (PAS+).

• Genetics: Associated with Von Hippel-Lindau (VHL) gene mutations.

⭐ Serous cystadenomas are virtually always benign; malignant potential is extremely low.

Mucin Monsters - Stroma & Duct Dilemmas

Two key mucinous cysts with malignant potential: Mucinous Cystic Neoplasm (MCN) & Intraductal Papillary Mucinous Neoplasm (IPMN). Differentiating them is crucial.

• Mucinous Cystic Neoplasm (MCN):

  • Predominantly in women (95%); body/tail of pancreas.
  • NO communication with pancreatic duct system.
  • Hallmark: Ovarian-type stroma (pathognomonic).
  • Cyst fluid: ↑CEA common.
  • Management: Surgical resection generally advised.

• Intraductal Papillary Mucinous Neoplasm (IPMN):

  • Originates from pancreatic duct epithelium; communicates with ducts.
  • Typically older males; pancreatic head common.
  • Types:
    • Main Duct (MD-IPMN): MPD dilated >5mm (often ≥10mm for high-risk); high malignant risk.
    • Branch Duct (BD-IPMN): Cystic dilations of side branches; lower risk.
    • Mixed Type: Involves both; behaves like MD-IPMN.
  • 📌 Involves Pancreatic Main Network (IPMN connects to ducts).

⭐ Fukuoka guidelines critical for IPMN: Resect MD-IPMNs & BD-IPMNs with high-risk stigmata (mural nodule ≥5mm, MPD ≥10mm, jaundice).

SPN Surprises - Young & Enigmatic

• Aka: Solid Pseudopapillary Neoplasm (SPN), Frantz tumor.
• Epidemiology: Predominantly young females (20-30 years); F:M >10:1.
• Location: Often pancreatic body or tail.
• Nature: Low-grade malignant potential; excellent prognosis with complete resection.
• Gross: Well-circumscribed, encapsulated mass; solid and cystic components with hemorrhage and necrosis.
• Microscopy: Characteristic pseudopapillae; cells with uniform nuclei, eosinophilic cytoplasm; hyaline globules.
• IHC: Nuclear β-catenin+, Vimentin+, CD10+, CD56+, PR+.

⭐ Genetic Signature: Activating mutations in the CTNNB1 gene (encoding β-catenin) are nearly universal.

Cystic Face-Off - Clues & Choices

• SCA: Elderly F; microcystic ("honeycomb"); central scar; ↓CEA. Benign.
• MCN: Middle-aged F (95%); body/tail; ovarian stroma; ↑CEA. Resect (premalignant).
• IPMN: Elderly M; duct link; ↑CEA, ↑Amylase. MD-IPMN (resect); BD-IPMN (surveil/resect based on risk).
• SPN: Young F; solid & cystic; hemorrhagic. Resect (low-grade malignancy).

⭐ > MCNs almost exclusively occur in women and are characterized by ovarian-type stroma.

High‑Yield Points - ⚡ Biggest Takeaways

• Serous Cystadenoma (SCA): Benign, glycogen-rich cells, central scar, elderly women.
• Mucinous Cystic Neoplasm (MCN): Exclusively women, ovarian stroma, body/tail, premalignant.
• Intraductal Papillary Mucinous Neoplasm (IPMN): Involves ducts, older men, malignant potential; main duct IPMN is higher risk.
• Solid Pseudopapillary Neoplasm (SPN): Young women, low malignant potential, CTNNB1 mutations.
• Pancreatic Pseudocysts: Most common, no epithelial lining, history of pancreatitis.
• High CEA in MCN/IPMN; low in SCA.