Cytologically Yours: Unknowns: 201401: Case 5

Cytology

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Resident Questions

• Diagnosis?

• Mucinous Pancreatic Neoplasm
  • Includes two diagnostic entities:
    • Mucinous Cystic Neoplasm (MCN)
      • Most arise in the body and tail of the pancreas
      • Most occur in women between the ages of 40 and 50 years old
      • Do not arise from the pancreatic main duct
    • Intraductal Papillary Mucinous Neoplasm (IPMN)
      • Most arise in the head of the pancreas
      • Most occur in men older than 60 years old
      • Connect to the pancreatic main duct or one of its branches
      • Radiology shows dilatation of the pancreatic duct and its branches
      • Endoscopy will reveal thick mucin extruding from the ampulla
  • Both are considered high risk due to their association with dysplasia and underlying carcinoma
  • Distinction between the two on cytology alone is not recommended
  • Best diagnosis is "neoplastic cells present, pancreatic mucinous neoplasm"

• What are some of the cytologic features that lead you to the diagnosis?

• Abundant thick mucin that may look colloid like
• Mucin can be so thick and tenacious it may cause difficulty in aspirating and making smears
• Flat sheets and clusters of bland appearing columnar cells with abundant intracytoplasmic mucin
• Mucin fills the cytoplasm and displaces the nucleus to the periphery or base of the cell. This is unlike the apical mucin seen in gastric foveolar epithelium
• Atypia may be present depending on the presence and degree of dysplasia
• Single cells or groups trapped in mucus

• Differential diagnosis?

• Contaminant gastrointestinal
  • Brush border and interspersed goblet cells is seen in duodenal epithelium
  • May see abundant mucin from GI tract
  • Gastric epithelium is present in tissue fragments of uniform cuboidal cells
  • Punctate perinuclear staining with B72.3
• CAN NOT DIFFERENTIATE BETWEEN IPMN AND MCN ON CYTOLOGY ALONE

• What ancillary studies would you order?

• CEA levels are >200ng/mL in both MCN and IPMN
• Amylase will be high in IPMN and low in MCN (due to IPMN connection with the pancreatic duct)
• B72.3 has diffuse cytoplasmic staining in MCN and IPMN