| Abstract: | Abstract: A 69-year-old woman was referred to our hospital with discomfort on swallow ing. Endoscopic examination revealed a large elevated tumor with multiple nodules at the end portion of the duodenal bulbus. The diagnosis obtained by biopsy was tubular adenoma with severe atypia. Upper gastrointestinal series and CT showed a tumor ap proximately 3.5 cm in diameter and the possibility of malignancy could not be ruled out. Partial duodenectomy was performed. Macroscopically the tumor measured 4.7X 3.1 cm. Endoscopic appearance and operational specimen of the tumor mimicked so-called lateral spreading tumor (LST) of the colon, which spreads horizontally and cir-cumferentially along the wall. Microscopically the tumor involved the mucosal and sub-mucosal layers, with no invasion of the muscular layer. Pathological diagnosis of the resected specimen was a borderline lesion between well-differentiated adenocarcinoma and adenoma with severe atypia. Using polmerase chain reaction and hybridization protection assay (PCR-HPA), we identified a point mutation at codon 12 of the K-ras onco-gene from glycine (GGT) to alanine (GCT). The tumor stained negative for p53 on immunohistochemistry, and PCR non radioisotopic single strand conformational polymor phism (non RI PCR-SSCP) for the analysis of exons5–8 of the p53 gene was also negative. This case seemed to be a duodenal epithelial tumor mimicking colonic LST with a rather benign nature despite its large size. (Dig Endosc 1999; 11: 70–75) |
