Small early flat carcinoma

Colon tumor
Carcinoma
Small early flat carcinoma

Topic Completed: 1 August 2015

Revised: 14 January 2018, last major update August 2015

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PubMed Search: Small early flat carcinoma

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Table of Contents

Cite this page: Gonzalez R. Small early flat carcinoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/colontumorsmallearlyflat.html. Accessed June 16th, 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)