Duodenal Adenoma of Gastric Foveolar Phenotype in the Second Portion of the Duodenum

Abstract

We describe a rare case of duodenal adenoma of a gastric phenotype in the second portion of the duodenum. An 85-yearold Japanese man with a history of left nephrectomy was admitted to our hospital with a cerebral transient ischemia attack. Screening upper gastrointestinal endoscopy revealed a subpedunculated polyp with a reddish, erosive, glossy appearance, and a granular surface just above the papilla of Vater in the second portion of the duodenum, which on biopsy was diagnosed as a hyperplastic polyp. Hypotonic duodenography revealed a subpedunculated polyp with irregular granular surface, measuring approximately 20 mm in size, in the second portion of the duodenum. Endoscopic total resection for biopsy was performed. The histopathological examination of the polypectomied specimens revealed an adenoma with moderate dysplasia mimicking gastric foveolar epithelium or hyperplastic polyp accompanied by abundant mucin production. Immunohistochemistry revealed a complete gastric phenotype, suggesting it had probably arisen from heterotopic gastric mucosa. The present case is the eleventh case of duodenal neoplasia arising from heterotopic gastric mucosa and the sixth case of neoplasia with gastric phenotype found in the second portion of the duodenum reported in the world.

The pathology of gastric and duodenal polyps: current concepts

“…64 These lesions uniformly express MUC5AC, with scattered MUC6-positive cells, whereas intestinal adenomas can be labelled with CDX2, CD10 and MUC2. 64,73,74 APC and KRAS alterations are frequently identified in both non-syndromic and FAP-related intestinal adenomas (Table 1). DNA MMR abnormalities, TP53 and BRAF mutations are infrequent.…”

“…51 PGAs show diffuse and strong MUC6 and MUC5AC labelling, in contrast to the negative MUC6 staining in foveolar lesions. 64,74,78 Reactive Brunner gland proliferative lesions (e.g. Brunner gland hamartoma/hyperplasia) can be differentiated from PGAs primarily by their retained lobular architecture.…”

“…Based on limited data, it has been found that foveolar adenomas could have a higher tendency to harbour high‐grade dysplasia 64 . These lesions uniformly express MUC5AC, with scattered MUC6‐positive cells, whereas intestinal adenomas can be labelled with CDX2, CD10 and MUC2 64,73,74 . APC and KRAS alterations are frequently identified in both non‐syndromic and FAP‐related intestinal adenomas (Table 1).…”

“… 12,51 High‐grade lesions contain complex or cribriform glands, with an increased nucleus:cytoplasm ratio, prominent nucleoli, pleomorphism and loss of cell polarity 51 . PGAs show diffuse and strong MUC6 and MUC5AC labelling, in contrast to the negative MUC6 staining in foveolar lesions 64,74,78 …”

Duodenal Epithelial Polyps: A Clinicopathologic Review

“…Instead, in cases where the polyps were not completely excised, progression to adenocarcinoma with gastric phenotype has been documented. 60 Duodenal foveolar-type adenomas are very rare lesions, 19,39,62 representing approximately 2.7% of duodenal adenomas with gastric phenotype and have a median tumor diameter of 9.7 mm (range, 8-20 mm). All of these lesions are polypoid and histologically have a tubulovillous architecture with tall columnar epithelium resembling foveolar gastric epithelium with various degrees of dysplasia 19 (Figure 7).…”