Adenocarcinoma arising from a gastric duplication cyst with invasion to the stomach: a case report with literature review

Abstract

This report describes a rare case of adenocarcinoma arising from a gastric duplication cyst, with invasion to the stomach wall, in a 40 year old Japanese man. A cystic lesion was found between the stomach and the spleen. The cyst had a well circumscribed smooth muscle layer, corresponding to the muscularis propria of the stomach and the mucosa of the alimentary tract. A well differentiated adenocarcinoma was found within the duplication cyst, invading its serosa. Well differentiated adenocarcinoma was independently found in the fundus of the stomach; the tumour of the cyst was connected by fibrous tissue. Microscopically, there was neither adenocarcinoma in situ nor precancerous lesions, such as epithelial dysplasia, suggesting that the carcinoma derived from a gastric duplication cyst that invaded the stomach. Duplication cysts should be included in the differential diagnosis of cystic masses of the gastrointestinal tract, and the possibility of malignancy within these cysts should be considered.

Figure 1

Computed tomography revealed a cystic lesion (asterisk) of 7 cm in diameter, located between the stomach (st) and the spleen (sp).

Figure 2

The cystic lesion. (A) The cyst was 7 cm in diameter, unilocular, and contained dark serosanguinous fluid. The lumen was granular and the wall was elastic hard. (B) Microscopically, the cyst wall had a well circumscribed smooth muscle layer, which corresponded to the muscularis propria of the stomach (haematoxylin and eosin; original magnification, ×40). Within the cyst, (C) simple cuboidal epithelium and (D) ciliated pseudostratified epithelium were seen (haematoxylin and eosin; original magnification, ×200). (E) A well differentiated papillary tumour was seen (haematoxylin and eosin; original magnification, ×100). (F) The tumour cell has hyperchromatic, atypical nuclei, corresponding to conventional adenocarcinoma (haematoxylin and eosin; original magnification, ×400). (G) The cytoplasm of the tumour cells was immunopositive for human gastric mucin (NCL-HGM-45M1 antibody; avidin–biotin–peroxidase complex technique). (H) The carcinoma invaded the serosa of the cyst wall (haematoxylin and eosin; original magnification, ×100).

Figure 3

Adenocarcinoma in the stomach. (A) The protruding and ulcerative tumour (T), measuring 4.5 × 2.5 cm, was seen at the anterior wall of the fundus. (B) The tumour consisted of a well differentiated tubular or papillary adenocarcinoma (haematoxylin and eosin; original magnification, ×200.)