Serous Microcystic Adenoma of the Pancreas

Definition

• Benign pancreatic neoplasm composed of innumerable small cysts lined by bland clear cells

cogen rich cystadenoma

• Microcystic serous cystadenoma
• Serous cystadenoma

Covered separately

• Macrocystic / oligocystic serous adenoma
• Solid serous adenoma

Diagnostic Criteria

• Solitary, circumscribed lesion
• Innumerable small cysts
  • Most 1-5 mm
    • Scattered larger cysts
  • Sponge-like / honeycomb appearance
• Lined by single layer of flattened or cuboidal cells with clear cytoplasm
  • Abundant glycogen (PAS +, diastase digestible)
  • Rarely eosinophilic cytoplasm
  • Sharp cell borders
  • Occasional intracystic papillary projections
• Bland cytology
  • Small round/oval nuclei
  • No mitotic figures
• Central stellate scar frequently present
  • May calcify
  • Scant stroma otherwise
  • Occasionally entraps other elements
• Rarely may undergo cystic degeneration, mimicing pseudocyst (Panarelli)
• Very rare cases that present with local invasion or lymph node metastases are considered serous cystadenocarcinoma

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

Original posting / last update: 1/4/07, 6/17/12

Supplemental studies

Histochemistry

Immunohistology

Lining cells

Differential Diagnosis

• Mucinous cystic neoplasm
• Serous oligocystic adenoma
• Serous cystadenocarcinoma
• Solid pseudopapillary neoplasm
• Acinar cystadenocarcinoma
• Lymphangioma
• Lymphoepithelial cyst
• von Hippel Lindau syndrome

Serous Microcystic Adenoma	Mucinous Cystic Neoplasm of the Pancreas
Cuboidal clear epithelial lining	Mucinous lining
Occurs in males and females	Nearly all female
Lack ovarian type stroma	Ovarian type stroma
Many small cysts	Oligocystic or unilocular
Usually stellate central scar	Lacks central scar
Glycogen positive, mucin negative	Glycogen negative, mucin positive

Serous Macrocystic / Oligocystic Adenoma	Serous Microcystic Adenoma
Small number of larger, variably sized cysts	Innumerable small, uniform cysts
Lacks prominent scar	Frequent central scar
May occur in adults and infants	Not reported in infants

Serous Microcystic Adenoma	Serous Cystadenocarcinoma of the Pancreas
Circumscribed intrapancreatic mass	Requires vascular invasion, adjacent organ invasion or metastases

Serous Microcystic Adenoma	Solid Pseudopapillary Neoplasm of the Pancreas
True cysts lined by a single layer of cells	Variable thickness of lining of degenerate spaces
Occurs in males and females	Nearly all female
Median age 60's	Mean age 20's
Glycogen positive	Glycogen negative
Keratin positive	Keratin variable

Clear cell variant of solid pseudopapillary neoplasm is also reported to be glycogen negative

Serous Microcystic Adenoma	Acinar Cell Cystadenocarcinoma of the Pancreas
Lined by clear cells	Lined by cells with granular eosinophilic cytoplasm
Frequent central scar	Lacks central scar
PAS+, diastase sensitive	PAS+, diastase resistant
BCL10, trypsin, chymotrypsin negative	BCL10, trypsin, chymotrypsin positive

Serous Microcystic Adenoma	Lymphangioma
Lined by clear cells	Lined by endothelium
Keratin positive	CD31, CD34, D240 positive

Serous Microcystic Adenoma	Lymphoepithelial Cyst of the Pancreas
Lined by clear cells	Lined by squamous epithelium
Lacks lymphoid stroma	Prominent lymphoid stroma

von Hippel Lindau syndrome is associated with diffuse cystic transformation of the pancreas and occasionally with serous microcystic adenomas

Clinical

• Mean age in 60's
  • Rare under age 20
• Local symptoms in 2/3
  • Remainder are incidental findings
• Diffuse serous cystic lesions associated with von Hippel-Lindau syndrome considered separately
• Benign
  • Rare serous cystadenocarcinomas have been reported

Grading / Staging / Report

• Grading
  • Not applicable
• Staging
  • Not applicable
• Report
  • Comment that the lesion is 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

Bibliography

• Solcia E, Capella C, Kloppel G . Tumors of the Pancreas, Atlas of Tumor Pathology, AFIP Third Series, Fascicle 20, 1997.
• Bosman FT, Carneiro F, Hruban RH, Thiese ND (Eds). WHO Classifiication of Tumors of the Digestive System, IARC, Lyon 2010.
• Kosmahl M, Wagner J, Peters K, Sipos B, Kloppel G. Serous cystic neoplasms of the pancreas: an immunohistochemical analysis revealing alpha-inhibin, neuron-specific enolase, and MUC6 as new markers. Am J Surg Pathol. 2004 Mar;28(3):339-46.
• Yasuhara Y, Sakaida N, Uemura Y, Senzaki H, Shikata N, Tsubura A. Serous microcystic adenoma (glycogen-rich cystadenoma) of the pancreas: study of 11 cases showing clinicopathological and immunohistochemical correlations. Pathol Int. 2002 Apr;52(4):307-12.
• Compagno J, Oertel JE. Microcystic adenomas of the pancreas (glycogen-rich cystadenomas): a clinicopathologic study of 34 cases. Am J Clin Pathol. 1978 Mar;69(3):289-98.
• 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.
• Panarelli NC, Park KJ, Hruban RH, Klimstra DS. Microcystic serous cystadenoma of the pancreas with subtotal cystic degeneration: another neoplastic mimic of pancreatic pseudocyst. Am J Surg Pathol. 2012 May;36(5):726-31