Colon
Carcinoma
Mucinous adenocarcinoma
Author: Raul S. Gonzalez, M.D.
Editorial Board Member: Catherine E. Hagen, M.D.
Editor-in-Chief: Debra L. Zynger, M.D.
Last author update: 12 April 2021
Last staff update: 16 January 2025 (update in progress)
Copyright: 2002-2025, PathologyOutlines.com, Inc.
PubMed Search: Mucinous carcinoma colon
Table of Contents
Definition / general | Essential features | Terminology | Epidemiology | Sites | Pathophysiology | Clinical features | Prognostic factors | Case reports | Gross description | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Molecular / cytogenetics description | Sample pathology report | Differential diagnosis | Board review style question #1 | Board review style answer #1Cite this page: Gonzalez RS. Mucinous adenocarcinoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/colontumorcolloid.html. Accessed January 21st, 2025.
Definition / general
- WHO recognized subtype of colorectal carcinoma with mucin lakes comprising at least 50% of tumor mass, though utility of 50% cutoff is unclear (Histopathology 2019;74:406)
Essential features
- Most common subtype of colorectal carcinoma
- Mucin production easily observed on histology
- Some cases are microsatellite instability (MSI) high
- Unclear whether worse prognosis than conventional colorectal carcinoma
Terminology
- Variably called colloid carcinoma
Epidemiology
- Relatively common (10% of all colorectal carcinomas) (Cancer 1976;37:1891)
- Incidence is stable (Dis Colon Rectum 2005;48:1161)
Sites
- Usually arises in the right colon (J Clin Pathol 2012;65:381)
Pathophysiology
- Associated with microsatellite instability, though most mucinous carcinomas are not MSI high (Cancer 2005;103:2023, Am J Pathol 2001;158:527)
Clinical features
- Typically presents at more advanced stage and with greater nodal involvement than standard colorectal carcinoma (Dis Colon Rectum 1993;36:49, Gastroenterol Hepatol 2002;25:534)
- May recur locally following excision (World J Surg Oncol 2012;10:109)
Prognostic factors
- May have same or worse prognosis compared with standard colorectal carcinoma (Ann Oncol 2012;23:135, J Surg Oncol 2000;73:70)
Case reports
- 11 year old girl with colloid carcinoma of rectum (J Postgrad Med 1993;39:218)
- 77 year old man with large mucinous adenocarcinoma (Dig Surg 2003;20:69)
Gross description
- Exophytic, gelatinous mass
Gross images
Images hosted on other servers:
Causing intussusception
Cecal tumor
Arising in villous adenoma
Microscopic (histologic) description
- Adenocarcinoma with strips of tumor cells floating in large extracellular mucin lakes comprising at least half of tumor mass
- Signet ring cells (with intracellular mucin) may also be present but should comprise less than half of tumor
Microscopic (histologic) images
Contributed by Raul S. Gonzalez, M.D. and @what_will_kill_you on Instagram
Abundant extracellular mucin
Epithelial cells within mucin
Mucinous adenocarcinoma
Positive stains
- CDX2 (100%)
- MUC2 (100%)
- CK20 (98%)
- Beta catenin (nuclear) (64%)
- CK7 (19%, usually rectal)
- MUC6 (5%)
- Reference: Am J Surg Pathol 2011;35:1830
Molecular / cytogenetics description
- KRAS mutations more common and TP53 mutations less common than in standard colorectal carcinomas (Mod Pathol 2006;19:59)
Sample pathology report
- Ascending colon, resection:
- Mucinous adenocarcinoma, well differentiated (see synoptic report)
Differential diagnosis
- Colitis cystica profunda:
- May form a mass and demonstrate copious extracellular mucin but epithelium is clearly benign
- Signet ring cell carcinoma:
- More than half of tumor composed of signet ring cells
Board review style question #1
Which of the following is true about mucinous adenocarcinoma of the colorectum?
- It is the most common subtype of colorectal carcinoma
- It unequivocally has a better prognosis than standard colorectal carcinoma
- It usually affects pediatric patients
- Signet ring cells are always at least a minor component
Board review style answer #1
A. It is the most common subtype of colorectal carcinoma
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Reference: Mucinous adenocarcinoma
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Reference: Mucinous adenocarcinoma
