Adenocarcinoma In Situ Arising from Brunner's Gland Treated by Endoscopic Mucosal Resection

Abstract

An 86-year-old Japanese man was presented to our hospital for further investigation of duodenal adenocarcinoma. The tumor was endoscopically resected. Pathological analysis revealed coexistence of gastric foveolar metaplasia and a surrounding hyperplastic Brunner's gland, in addition to an adenocarcinoma component. Immunostaining for MUC5AC and MUC6 confirmed the diagnosis of adenocarcinoma in situ arising from Brunner's gland hyperplasia. This case suggests that although detailed preoperative evaluation is required to determine the depth of tumor invasion, endoscopic resection may be a promising option for the treatment of adenocarcinomas arising from Brunner's gland hyperplasia.

Figure 1

Endoscopic images. Esophagogastroduodenoscopy shows a solitary submucosal tumor in the duodenal second portion. The top of the tumor is slightly depressed, showing a reddish color on white light imaging (a, b) and a brownish color on narrow band imaging (c). Endoscopic ultrasonography reveals that the hypoechoic mass is mainly confined to the mucosal layer (d). A small cystic area is also seen (white arrow) (e).

Figure 2

Hypotonic duodenography image. A submucosal tumor with bridging folds is seen in the inferior duodenal angle.

Figure 3

Esophagogastroduodenoscopy images during endoscopic mucosal resection. A duodenal tumor is seen after indigo carmine spraying (a). After injection of hyaluronic acid solution into the duodenal submucosa, the tumor is completely resected with a bipolar snare (b, c).

Figure 4

Histopathological images. Proliferation of Brunner's glands is seen in the resected specimen (a: ×2, b: ×20). Gastric foveolar metaplasia is also identified (a: blue square, c: ×10). Atypical cells with pleomorphic macronuclei with dense chromatin forming irregular glandular structure are found in the superficial layer (a: red square, d: ×20). Hematoxylin and eosin staining.

Figure 5

Immunohistochemical images. Proliferated Brunner's glands are positive for MUC6 (a, white arrow) and negative for MUC5AC (b, white arrow). In contrast, most of the cells with gastric foveolar differentiation (a, black arrowhead; b, black arrowhead) and atypical cells (a, black arrow; b, black arrow) are positive for MUC5AC but are negative for MUC6. Both gastric foveolar metaplasia and atypical cells partly show dual positivity for MUC5AC and MUC6, particularly in the deeper layer (a, arrowhead; b, arrowhead). Some atypical cells showed relatively higher positivity for Ki-67 staining (c, hematoxylin and eosin staining, arrows).