The duodenal specimens were composed of 567 benign lesions and 48 malignant lesions. In this report, the benign duodenal lesions were described. The 567 benign lesions were composed of chronic non-specific duodenitis in 334 cases (60.0%), duodenal ulcer in 101 cases (17,8%), heterotopic gastric mucosa in 81 cases (14.3%), hyperplastic polyp in 16 cases (2.8%), Brunner's gland hyperplasia in 14 cases (2.5%), Brunner's gland adenoma in 8 cases (1.4%), lymphoid polyp in 5 cases (0.8%), tubular adenoma in 4 cases (0.7%), lymphagioma in 2 cases (0.4%), endocrine cell micronests in 1 case (0.2%), and amyloidosis in 1 case (0.2%).
The chronic non-specific duodenitis (n=334) was characterized by edema and lymphocytic infiltration (). This condition was very frequently recognized. Almost all duodenal specimens showed more or less lymphocytic infiltration.
Chronic duodenitis. Much lymphocytes infiltration is seen. HE, x200.
The duodenal ulcer (n=101) was characterized by exudate, necrosis, granulation tissue and regenerative epithelium (). The regenerative epithelium infrequently mimicked adenocarcinoma. No evidence for viral or fungal infection was noted in the present series. The location was fist portion in 87 cases, and second portion in 14 cases. Perforation of the ulcer was recognized in two cases, which needed emergency operations.
Duodenal ulcer. Necrosis, exudates, infiltration of neutrophils and lymphocytes are recognized. HE, x200.
The hererotopic gastric mucosa (n=81) was located in the first portion in 42 cases, second portion in 32 cases, and third portion in 7 cases. Endoscopically, it was recognized as slight elevated or discolored lesion. Heterotopic gastric mucosa consisted of the following two types: one was composed of only foveolar epithelium (n=21) () and another foveolar epithelium and fundic glands (n=60) (). The foveolar epithelium occasionally showed hyperplastic changes ().
Heterotopic gastric mucosa of the duodenum. A: Gastric foveolar epithelium is recognized. HE, x100. B: Gastric fuveolar epithelium and fundic glands are seen. HE, x200.
The hyperplastic polyp (n=16) was located in the first portion in 9 cases, in the second portion in 5 cases and in the third portion in 2 cases. Endoscopically, it was detected as duodenal polyp. Histologically, it was composed of hyperplastic columnar epithelium with mucins, and resembled to hyperplastic polyp of the stomach ().
Hyperplastic polyp of the duodenum. Hyperplasia of gastric foveolar-like cells is recognized. HE, x100.
The Brunner's gland hyperplasia (n=14) was located in the first portion in 9 cases and the second portion in 5 cases. Endoscopically, it was recognized as an elevated or polyp lesion. It was histologically characterized by hyperplastic proliferation of the gland. However, in biopsy specimens, differentiation from Brunner's gland adenoma was occasionally difficult.
The Brunner gland adenoma (n=8) was situated in the first portion in 3 cases and the second portion in 5 cases. Endoscopically, it was recognized as a polypoid elevation or polyp lesion. It was histologically characterized by neoplastic proliferation of the gland ().
Brunner's gland adenoma. Neoplastic Brunner's gland is noted. No atypia is seen. HE, x100
The lymphoid polyp (n=5) was present in the first portion in 2, second portion in 2, and third portion in 1 cases. Endoscopically, it was recognized as a polyp. It was histologically characterized by a large lymph follicle with a large germinal center (). The histology and imunohistochemical study demonstrated that it was different from follicular lymphoma and other types of lymphoma.
Lymphoid polyp of the duodenum. Hyperplastic lymph follicle is recognized. HE, x40
The tubular adenoma (n=4) was located in the first portion in 1 case, second portion in 2 cases, and third portion in 1 case. Endoscopically, it was recognized as flat or elevated lesions. It was histologically characterized by adenomatous proliferation of intestinal epithelium (), similar to colon adenoma. Immunohistochemically, the tubular adenoma was negative for p53 protein, and Ki-67 labeling was low (mean Ki-67 labeling = 8%).
Tubular adenoma of the duodenum. Adenomatous proliferation of intestinal epithelium is recognized. The appearances are similar to colonic adenoma. HE, x200.
The lymphangioma (n=2) was present in the second portion in all the two cases. Endoscopically, it was recognized as polyp or submucosal tumor. Pathologically, it was characterized by submucosal cavernous proliferation of lymphatics free of red blood cells (). No atypia was recognized.
Lymphagioma of the duodenum. Neoplastifc proliferation of lymphatics is recognized. HE, x100.
The endocrine cell micronests (n=1) was located in the second portion. Endoscopically, it was recognized as a flat discolored lesion. It was pathologically characterized by non-neoplasmic proliferation of neuroendocrine cells positive for synaptophysin, neuro- specific enolase, and CD56.
In amyloidosis (n=1), biopsy was taken from the bulb. Endoscopically, it was recognized as a polyp. Pathologically, it was characterized by deposition of amorphous materials () positive with Congo-red stain (). Later the patient (76-year-old man) was found to have multiple myeloma.
Amyloidosis of the duodenum A: Red amorphous substance is noted in the mucosa. HE, x100 B: The substance is positive with Congo-red stain. Congo-red stain, x100.