Pancreatic mass

Clinical history: A 65-year-old gentleman presented with painless obstructive jaundice and imaging studies revealed a 3.4 cm mass in the head of the pancreas. Endoscopic ultrasound-guided fine needle aspirate of the mass was performed.

Cytologic findings

The smears show two distinct cell populations:

Benign pancreatic acinar cells:
- Cohesive "grape-like" aggregates
- Polygonal-shaped acinar cells
- Nuclei: eccentric, round, evenly distributed fine granular chromatin.
Malignant cells:
- Irregular clusters with overlapping nuclei ("drunken honeycomb")
- Isolated single cells with marked atypia
- Moderate to marked cytologic atypia:
  - Nuclear membrane: notches, grooves, convolutions
  - Nuclear size: enlarged, anisonucleosis (>4:1 in one sheet)
  - Chromatin clumping and nuclear clearing
  - Mitoses
- Cytoplasmic mucin vacuoles

Diagnosis

Case writer: Dr Noel Chia

EUS-FNA 1

Pancreatic mass