early gastric carcinoma
Saturday 16 February 2013
Early gastric carcinoma is defined as invasive carcinoma confined to mucosa and/or submucosa, with or without lymph node metastases, irrespective of the tumor size.
Most early gastric carcinomas are small, measuring 2 to 5 cm in size, and often located at lesser curvature around angularis. Some early gastric carcinoma can be multifocal, often indicative of a worse prognosis.
Grossly, early gastric carcinoma is divided into:
Type I for the tumor with protruding growth,
Type II with superficial growth,
Type III with excavating growth,
Type IV for infiltrating growth with lateral spreading.
Type II tumor is further divided to IIa (elevated), IIb (flat) and IIc (depressed), as proposed by the Japanese Endoscopic Society.
A more recent Paris classification has endorsed three gross patterns for superficial neoplastic lesions in gastrointestinal tract.
Grossly and endoscopically, the tumor is classified as:
Type 0-I for polypoid growth (which is subcategorized to 0-Ip for pedunculated growth and 0-Is for sessile growth),
Type 0-II for nonpolypoid growth (which is subcategorized into:
- Type 0-IIa for slightly elevated growth,
- Type 0-IIb for flat growth,
- Type 0-IIc for slightly depressed growth),
Type 0-III for excavated growth.
Histologically, the most common forms of early gastric carcinoma are well differentiated, mostly with tubular and papillary architecture.
The distinction between well-differentiated carcinoma and high grade dysplasia or carcinoma in situ can be challenging when only mucosal tissue is available for histologic assessment.
Intramucosal invasion may not be as easily confirmed as an invasive carcinoma into submucosa where stromal desmoplasia is usually evident.
The distinction between "intramucosal carcinoma" and "carcinoma in situ" or "high grade dysplasia" is important, as the intramucosal carcinoma of stomach, unlike the intramucosal carcinoma in the colon, does metastasize.
Generally, the useful histologic features of intramucosal invasion are single tumor cells in the lamina propria and significantly fused neoplastic glands of various sizes.
The prognosis of early gastric carcinoma is excellent, with a 5 years survival rate as high as 90%.
advanced gastric carcinoma