Pancreas
Exocrine tumors / carcinomas
Mucinous cystic neoplasm (MCN)

Author: Deepali Jain, M.D. (see Authors page)

Revised: 15 December 2017, last major update August 2012

Copyright: (c) 2002-2017, PathologyOutlines.com, Inc.

PubMed Search: Mucinous cystic neoplasm[TI] pancreas

Cite this page: Jain, D. Mucinous cystic neoplasm (MCN). PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/pancreasmcn.html. Accessed February 20th, 2018.
Definition / general
  • Benign or potentially low grade malignant cystic epithelial neoplasm composed of cells which contain intracytoplasmic mucin (IARC: 8470 / 0 Mucinous Cystoma [Accessed 15 December 2017])
  • One of three precursor lesions of pancreatic adenocarcinoma (also PanIN, IPMN)
  • WHO Classification: with low or intermediate grade dysplasia, with high grade dysplasia or with an associated invasive carcinoma
Clinical features
  • Almost always women, mean age 45 years
  • Abdominal pain or mass
  • < 20% associated with invasive carcinoma
  • Metastases usually restricted to abdominal cavity; metastases to ovary may simulate primary ovarian tumors
  • Can also occur in the liver
  • Rarely associated with anaplastic carcinoma (World J Gastroenterol 2008;14:132, Arch Pathol Lab Med 1997;121:1104) or sarcomatous stroma with aggressive behavior
Case reports
Gross description
  • Large (mean 10 cm)
  • Usually in body / tail, multilocular (occasionally unilocular) megacysts that don't communicate with ductal system unless fistula are present
  • Cyst wall is papillary, trabecular or thickened
  • Has mucoid / watery cyst contents
  • Must sample solid areas within the cyst
Gross images

Images hosted on PathOut server:

Unilocular cyst

Conspicuous, irregular, solid protuberances

Multiloculated cystic lesion

Invasive tumor from tail of pancreas in 36 year old woman shows large cyst with solid tumor



Images hosted on other servers:

39 year old man with multilocular cyst with thick mucin

Microscopic (histologic) description
  • Lined by tall mucin producing cells, often forming papillae
  • Intestinal or gastric foveolar type features
  • Calcification common
  • Ovarian type stroma is relatively specific; recapitulates fetal pancreatic mesenchyme around ducts (ER+, PR+, inhibin+)
  • May have mural nodules with features of giant cell tumor, MFH or anaplastic carcinoma
  • Endocrine cells often scattered among columnar lining cells
  • Note: must sample extensively to rule out an invasive component (Am J Surg Pathol 1999;23:1320)
Microscopic (histologic) images

Images hosted on PathOut server:

Adenoma

Cyst wall containing lobular glands

Cyst wall with focal hyalinization

Foreign body reaction


Low grade dysplasia

Intermediate grade dysplasia

High grade dysplasia


Invasion: lining epithelium is desquamated

Invasion: cribriform architecture

36 year old woman

Scattered endocrine cells are serotonin+



Images hosted on other servers:

Mucinous cystic neoplasm

Low grade dysplasia

Squamous metaplasia

Positive stains
Negative stains
Molecular / cytogenetics description
  • Molecular analysis suggests monoclonal origin with subsequent divergence for cases with sarcomatous stroma (Mod Pathol 2000;13:86, Am J Surg Pathol 1997;21:70)
  • KRAS mutations noted in in situ or invasive areas, inactivating SMAD4 and TP53 mutations in more advanced MCNs
  • Cyst fluid analysis: higher expression of microRNAs in mucinous precursors, low amylase levels
Differential diagnosis