Pancreas
Exocrine tumors / carcinomas
Colloid (mucinous noncystic) carcinoma

Author: Wei Chen, M.D., Ph.D (see Authors page)
Editorial Board Member Review: Raul S. Gonzalez, M.D.

Revised: 27 June 2017, last major update May 2017

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

PubMed Search: Colloid mucinous noncystic carcinoma

Cite this page: Colloid (mucinous noncystic) carcinoma. PathologyOutlines.com website. http://pathologyoutlines.com/topic/pancreascolloid.html. Accessed September 19th, 2017.
Definition / general
  • An infiltrating ductal epithelial neoplasm of the pancreas characterized by the presence (in at least 80% of the neoplasm) of large extracellular stromal mucin pools containing suspended neoplastic cells (WHO)
Essential features
  • > 80% of the tumor volume composed of mucin pools with scanty floating tumor cells
  • Associated with intraductal papillary mucinous neoplasm (IPMN), (almost always arise in an intestinal type IPMN), mucinous cystic neoplasm and ampullary / duodenal tubulovillous adenomas
  • Better survival compared to usual ductal adenocarcinoma (UDA)
Terminology
  • Colloid carcinoma
  • Mucinous noncystic carcinoma
  • Gelatinous carcinoma
ICD-10 coding
  • C25
Epidemiology
  • 1 - 3% of malignant neoplasms of the exocrine pancreas
  • 27 - 70% of IPMN with associated invasive adenocarcinoma have a colloid component (Pathology 2008; 40:655)
Sites
  • Usually in the head of pancreas
Pathophysiology
  • Inverse polarization of cells (mucin glycoproteins in stroma facing surfaces vs luminal surface or diffuse in UDA)
  • Expression of MUC2 (gel forming mucin) (rare in UDA) and the absence of external lamina or basement membrane may lead to accumulation of extracellular mucin, which limits tumor spread and appears to have tumor suppressor activity (Am J Surg Pathol 2003;27:571, Mod Pathol 2002;15:1087)
Clinical features
  • Mean age 61 years
  • Male = Female
  • Abdominal / epigastric pain (in contrast to back pain of UDA), pancreatitis (50% patients), diarrhea, jaundice, weight loss
  • Larger, compared to UDA (6.0 cm), lower stage, better survival
  • Incisional biopsy may contribute to thromboembolic complications (Am J Surg Pathol 2001; 25:26)
  • Pseudomyxoma peritonei can be a rare complication
Diagnosis
  • Based on extensively sampled resection specimen
Radiology description
  • Dilated ducts (sometimes filled with nodular lesions)
Prognostic factors
  • 5 year survival 57% (vs 12% for resectable UDA) (Am J Surg Pathol 2001; 25:26)
  • Tumor diameter, presence of IPMN / mucinous cystic neoplasm (MCN) structures, surgical margin status, vascular or perineural invasion, lymph node status, Kras mutation, or p53 mutation are not prognostic factors (Am J Surg Pathol 2001; 25:26)
Case reports
Treatment
  • No specific treatment guidelines
Gross description
  • Large (mean 5 cm), well demarcated tumor
  • Solid, firm, gelatinous cut surface
Gross images

Images hosted on PathOut server:

Whipple resection specimen

Microscopic (histologic) description
  • At least 80% of the neoplasm consists of large extracellular stromal mucin pools
  • Scanty carcinoma cells suspended within these mucin pools
    • Usually cuboidal or columnar cells
    • Cribriform or stellate clusters, strips of columnar cells, small tubules or signet ring cells
  • Incomplete lining of mucin lakes common
  • Mucin tends to be retained during histologic processing (in contrast to IPMN and MCN)
  • Muconodular invasive component of 1 cm or more
  • Usually arise in association with IPMN, MCN or tubular / tubulovillous adenoma
  • Perineural invasion and regional lymph node metastasis common
Microscopic (histologic) images

Images hosted on PathOut server:

Large mucin pools are partially lined by
well differentiated cuboidal to columnar
neoplastic cells and contain clumps or
strands of neoplastic cells



Images hosted on other servers:

Large mucin pools are partially lined by well differentiated cuboidal to columnar neoplastic cells and contain clumps or strands of neoplastic cells

MUC2+

Cytology description
  • Difficult to spread thinly on slides due to abundant mucus
  • Cellularity of malignant cells may be low
Cytology images

Images hosted on other servers:

Fig 1: abundant mucinous material, degenerated inflammatory cells, rare 3D fragments of benign appearing epithelium
Fig 2: cytologic atypia with enlarged, crowded, hyperchromatic nuclei
Fig 3: numerous single cells with large solitary intracytoplasmic vacuoles consistent with mucin

Positive stains
  • Strong expression of CDX2 and MUC2 (indicating intestinal differentiation); UDA usually MUC2-
  • CEA shows accentuated staining in basal aspects of tumor cells (luminalization), in addition to luminal staining
  • May show focal reactivity for synaptophysin or chromogranin
Negative stains
Electron microscopy description
  • Mucigen granules on stromal surface, no basement membrane
Molecular / cytogenetics description
  • KRAS codon 12 mutation (33%), less frequent than ordinary ductal adenocarcinoma ( > 90%)
  • TP53 mutation (22%)
  • Microsatellite stable unlike mucinous carcinomas of colon (Mod Pathol 2003; 16;537)
Differential diagnosis
  • Extravasated benign stromal mucin: mucus lakes limited to periductal location, devoid of neoplastic cells; frequently inflamed
  • IPMN: smooth contours, complete epithelial lining, intraluminal mucin lost during processing
  • Mucinous cystic neoplasm: ovarian type stroma; usually women; no association with IPMN
  • Conventional ductal adenocarcinoma: intracytoplasmic and luminal mucin; no or scant stromal mucin
Board review question #1
A 62 year old women presented with pancreatic head mass. Histologic sections demonstrate areas of irregular mucin pools with suspended clusters of malignant cells and also floating signet ring cells. However, no individual infiltrating signet ring cells are identified in the stroma. There is an intestinal type IPMN in the background; no conventional ductal adenocarcinoma component is seen. What’s the diagnosis?

  1. Colloid carcinoma (mucinous noncystic neoplasm)
  2. IPMN with rupture and extruded stromal mucin
  3. Mucinous cystadenocarcinoma
  4. Signet ring cell carcinoma
Board review answer #1
A. Colloid carcinoma (mucinous noncystic neoplasm)