Acinar Cell Cystadenoma of the Pancreas

Definition

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

Alternate/Historical Names

• Cystic acinar transformation

Diagnostic Criteria

• 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

Original posting/updates: 1/2/08, 4/26/09, 1/2/12, 12/30/12

Supplemental studies

Immunohistology

Differential diagnosis

• Distinction from serous and mucinous cystic lesions is made by identification of the nature of the lining cells
• Acinar cell cystadenocarcinoma

Clinical

• Mean age 49
• Very rare
• Benign

Lists

Cystic Pancreatic Lesions

• Acinar cell cystadenocarcinoma
• Acinar cell cystadenoma
• Enterogenous duplication cyst
• Epidermoid cyst in intrapancreatic accessory spleen
• Intraductal oncocytic papillary neoplasm
• Intraductal papillary mucinous neoplasm
• Islet cell / well differentiated neuroendocrine tumor (occasionally cystic)
• Lymphangioma
• Lymphoepithelial cyst
• Mucinous cystic neoplasm
• Paraduodenal wall cyst
• Pseudocyst
• Serous cystadenocarcinoma
• Serous oligocystic adenoma
• Serous microcystic adenoma
• Solid and cystic hamartoma
• Solid pseudopapillary neoplasm
• Squamoid cyst of pancreatic ducts
• von Hippel Lindau associated cystic lesions

Pancreatic Acinar Cell Lesions

• Acinar cell carcinoma
• Acinar cell cystadenoma
• Acinar cell Nodule
• Mixed acinar carcinomas
  • Acinar-ductal carcinoma
  • Acinar-endocrine carcinoma
• Pancreatoblastoma

Bibliography

• Hruban RH, Pitman MB, Klimstra DS. Tumors of the Pancreas, Atlas of Tumor Pathology, AFIP Fourth Series, Fascicle 6, 2007.
• Bosman FT, Carneiro F, Hruban RH, Thiese ND (Eds). WHO Classifiication of Tumors of the Digestive System, IARC, Lyon 2010.
• Klimstra DS. Nonductal neoplasms of the pancreas. Mod Pathol. 2007 Feb;20 Suppl 1:S94-112.
• Zamboni G, Terris B, Scarpa A, Kosmahl M, Capelli P, Klimstra DS, Lam PW, Klöppel G. Acinar cell cystadenoma of the pancreas: a new entity? Am J Surg Pathol. 2002 Jun;26(6):698-704.
• Albores-Saavedra J. Acinar cystadenoma of the pancreas: a previously undescribed tumor. Ann Diagn Pathol. 2002 Apr;6(2):113-5.
• Chatelain D, Paye F, Mourra N, Scoazec JY, Baudrimont M, Parc R, Flejou JF. Unilocular acinar cell cystadenoma of the pancreas an unusual acinar cell tumor. Am J Clin Pathol. 2002 Aug;118(2):211-4.
• Basturk O, Coban I, Adsay NV. Pancreatic cysts: pathologic classification, differential diagnosis, and clinical implications. Arch Pathol Lab Med. 2009 Mar;133(3):423-38.
• Khor TS, Badizadegan K, Ferrone C, Fernández-del Castillo C, Desai GS, Saenz A, Le L, Lauwers GY, Deshpande V. Acinar cystadenoma of the pancreas: a clinicopathologic study of 10 cases including multilocular lesions with mural nodules. Am J Surg Pathol. 2012 Nov;36(11):1579-91