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Table of Contents
Definition / general | Epidemiology | Sites | Pathophysiology | Etiology | Clinical features | Diagnosis | Prognostic factors | Case reports | Treatment | Gross description | Microscopic (histologic) description | Microscopic (histologic) images | Molecular / cytogenetics descriptionCite this page: Gonzalez R. Small early flat carcinoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/colontumorsmallearlyflat.html. Accessed February 17th, 2019.
Definition / general
- Term used primarily in Japan for low stage colorectal carcinomas with flat configuration
- Not widely diagnosed in the USA; not officially recognized by the WHO
Epidemiology
- Represents 6% - 10% of colonic cancers diagnosed in Japan
- Does occur in Western countries (Gut 2002;51:550)
Sites
- Usually develops in the right colon, in older patients (Dis Colon Rectum 2005;48:101)
Pathophysiology
- May develop from flat adenomas, which are more likely to harbor malignancy than polypoid ones (JAMA 2008;299:1027)
- May be an important precursor of advanced malignancies (Ann Acad Med Singapore 2003;32:263)
- Tend to invade submucosa at a smaller size than polypoid lesions (Ann Pathol 2002;22:18)
Etiology
- p53 dependent apoptosis may play a role in development (Dis Colon Rectum 2000;43:S23)
Clinical features
- May act aggressively despite small size
Diagnosis
- Flat lesions may be easier to detect using chromoscopy (spraying dye on mucosa during colonoscopy) (Int J Clin Oncol 2006;11:1)
Prognostic factors
- Tumors with central depression tend to rapidly invade submucosa (World J Surg 2000;24:1075)
Case reports
- 52 year old man with primary minute invasive de novo colonic adenocarcinoma appearing as submucosal tumor (Int J Gastrointest Cancer 2005;36:177)
- 81 year old woman with early colonic carcinoma with extensive lymph node metastases (Int J Colorectal Dis 2001;16:262)
Treatment
- May be curable using endoscopic mucosal resection
Gross description
- Flat, plaque-like lesion, often with central depression
- Malignancy typically measures 1 cm or less
Microscopic (histologic) description
- Adenocarcinoma limited to mucosa or submucosa, by definition
- Height is usually less than twice the height of adjacent normal mucosa
- Architectural changes mild; cytologic features resemble high grade dysplasia
Microscopic (histologic) images
Images hosted on other servers:
Invasion of submucosa (Figure 4)
Molecular / cytogenetics description
- Loss of heterozygosity of 17p, 18p, 18q, and 22q, coupled with LOH of other loci (Ann Oncol 2006;17:43)
