Acinar Cell Cystadenoma of the Pancreas

Definition

Benign cystic lesion of the pancreas lined by cells exhibiting acinar differentiation

Wide range of cystic architectural patterns
- Unilocular to multilocular
- Cysts may range from minimally dilated acini to prominent cyste
- Solitary to multiple
  - One diffuse case reported
- Intracystic nodules may be present
Only rarely communicates with duct system
Cysts lined by bland cells with acinar differentiation
- Moderate to abundant granular eosinophilic cytoplasm
  - PAS positive diastase resistant
  - Usually apical
- Basal cytoplasm may be basophilic
- Lining may be multilayered
  - Lumenal cells may be attenuated
  - May be focally lined by normal appearing ductal cells or squamous cells
- May form acini in areas
- May be associated with ducts lined by mucinous columnar epithelium / low grade PanIN
Cytologically bland
- May have at most mild atypia
- Nucleoli present but small
- Mitotic figures absent
No invasion
No solid acinar cell adenomas have been reported

Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342