Duodenal mucosal damage is associated with proliferative activity of Brunner’s gland hamartoma: a case report

Abstract

BackgroundBrunner’s gland hamartoma is a rare tumor, predominantly found in the fifth to sixth decades of life. Generally, it is a single pedunculated polyp, rarely larger than 5 cm. Asymptomatic cases are found incidentally, but cases with a large polyp tend to have gastrointestinal bleeding and/or obstructive symptoms. Polyp size increases in a time-dependent manner, however, the growth mechanism is unknown. We report a Japanese male case in his mid-twenties with an over 6 cm sized polyp.Case presentationA 26-year-old man presented black stools and anemia. Endoscopic examination revealed a large pedunculated polyp at gastroduodenal junction. The polyp, subsequently resected by distal gastrectomy, was lobulated with random surface erosions and sized 6.4 × 3 cm. Histological examination revealed that the polyp arose from duodenal mucosa and was composed of hyperplastic Brunner’s glands in lobules separated by fibromuscular septa, associated with lymphocytic infiltrate and lymphoid follicles. No evidence of malignancy was found. Thus, the lesion was diagnosed as Brunner’s gland hamartoma. Further immunohistochemical studies indicated that gastric foveolar metaplasia is associated with surface epithelium covering upper two thirds of the polyp, showing immunohistochemical positivity for mucin 5 AC (MUC5AC). Below the metaplastic surface epithelium, Brunner’s glands had high proliferative activity (MIB-1 labeling index: 7.9%). The similar staining pattern was observed at surface erosive sites (MIB-1 labeling index in Brunner’s glands: 9%). On the other hand, surface epithelium in the lower side of the polyp still preserved intestinal nature, containing CDX2-positive nuclei and MUC2-positive goblet cells. Brunner’s glands below the surface epithelium with intestinal characteristics showed low proliferative activity (MIB-1 labeling index: 0.77%).ConclusionProliferative activity of Brunner’s glands was high at the sites with surface erosion and also below the epithelium showing gastric foveolar metaplasia. As gastric foveolar metaplasia occurs along with a mucosal repair process in the duodenum, mucosal damages underlay the hamartomatous proliferation of Brunner’s glands and eventually resulted in a formation of large polypoid mass in this case.

Brunner’s Gland Hyperplasias and Hamartomas in Association with Helicobacter pylori

“…The pathogenesis of proliferative lesions of BGs has not yet been completely elucidated [1]. The main aetiology is suggested to be a chronic local irritation in the duodenal mucosa [26]. The major factors studied in mucosal injury are gastric hyperacidity, mechanical stimuli in the duodenum and H. pylori infections [26, 27].…”

“…The main aetiology is suggested to be a chronic local irritation in the duodenal mucosa [26]. The major factors studied in mucosal injury are gastric hyperacidity, mechanical stimuli in the duodenum and H. pylori infections [26, 27]. It has been reported that BG hyperplasia especially develops in patients with chronic gastritis and duodenal ulcers in the presence of hyperchlorhydria [13, 20].…”

Saving from unnecessary pancreaticoduodenectomy. Brunner's gland hamartoma: Case report on a rare duodenal lesion and exhaustive literature review

“…also suggested an immunohistochemical connection between BGH proliferative activity and gastric foveolar metaplasia [24].…”

Brunner's glands hamartoma as an unusual cause of gastrointestinal gbleedin

“…Los hamartomas son lesiones que contiene múltiples elementos tisulares, acinos, conductos, fibras musculares lisas, tejido adiposo y linfoide e incluso heterotopia pancreática y que macroscópicamente suele corresponderse con pólipos únicos mayores de 5 mm, sésiles o pediculados (3) . Existe controversia si este tipo de lesiones deben ser clasificadas como hiperplasia, hamartomas o proliferaciones adenomatosas.…”