Table of Contents
Definition / general | 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 | Differential diagnosis | Additional referencesCite this page: Gonzalez R. Mucinous. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/colontumorcolloid.html. Accessed January 22nd, 2021.
Definition / general
- WHO recognized subtype of colorectal carcinoma with mucin lakes comprising at least 50% of tumor mass
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
- Most commonly arises in the right colon (J Clin Pathol 2012;65:381)
Pathophysiology
- Associated with microsatellite instability (Cancer 2005;103:2023), though most mucinous carcinomas are not MSI-high (Am J Pathol 2001;158:527)
Clinical features
- Usually presents at more advanced stage (Dis Colon Rectum 1993;36:49) and with greater nodal involvement (Gastroenterol Hepatol 2002;25:534) than standard colorectal carcinoma
- May recur locally following excision (World J Surg Oncol 2012;10:109)
Prognostic factors
- May have same (Ann Oncol 2012;23:135) or worse (J Surg Oncol 2000;73:70) prognosis compared to standard colorectal carcinoma
Case reports
- 11 year old child 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
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
Positive stains
- CDX2 (100%), MUC2 (100%), CK20 (98%), beta-catenin (nuclear) (64%), CK7 (19%, usually rectal), MUC6 (5%) (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)
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
Additional references