Abstract: A control Sprague-Dawley male rat from the control group of a repeated dose toxicity study had a mucinous adenocarcinoma in the ileum. The gross morphology showed that 3 nodules in the serosal layer of ileum were observed, with the size of 1.4 cm 1.3 cm, 0.7 cm × 0.5 cm and 0.4 cm × 0.3 cm, respectively. HE staining showed that the neoplasm was primarily composed of cuboidal or columnar and goblet cells which were arranged in a glandular form. Alcian blue-PAS staining revealed the expression of mucin in neoplastic cells and in the lumen. The above results are in line with the diagnostic features of mucinous adenocarcinoma in the ileum.

Key words: Mucinous adenocarcinoma, Ileum, Rats