Brunner gland hamartoma with predominant adipose tissue and ciliated cysts.

We report a case of Brunner gland hamartoma of the duodenal bulb with unusual histologic features. The lesion was composed predominantly of adipose tissue and comprised multiple cysts with a lining epithelium rich in ciliated cells.

REPORT OF A CASE

A 43-year-old man with no significant previous medical history presented with regurgitation. The onset of symptoms began abruptly, 2 days before presentation. Abdominal ultrasonography revealed the presence of a cystic lesion with large septa between the gastroduodenal junction and the head of the pancreas. Computed tomographic scan showed a well-demarcated, hypodense lesion in the duodenal wall, and endoscopy of the upper digestive tract revealed the presence of a pedunculated tumor of the duodenal bulb, narrowing the duodenal lumen on a radiographic series of the upper gastrointestinal tract. Surgical resection of the antrum and first duodenum was performed. The patient's postoperative course was unremarkable.

MATERIALS AND METHODS

The surgical specimen included a whitish polypoid tumor measuring 3.5 cm and containing a few cysts, which were up to 1 cm in diameter The specimen was fixed in 10% formalin and embedded in paraffin, and 3-[micro]m sections were stained with hematoxylin-eosin.

RESULTS

On microscopic examination, the polypoid lesion was covered by normal duodenal mucosa. The lesion was located in the submucosa and was composed mainly of prominent mature adipose tissue containing few capillaries and nerves (Figures 1 and 2). There were also hyperplastic lobules of Brunner gland, lined by cylindrical clear mucinous cells with basal hyperchromatic nuclei (Figures 1 and 2). The lesion contained numerous dilated ducts measuring from 0.1 to 1 cm in diameter (Figures 1 and 2). These ducts were lined either by cylindrical eosinophilic cells or by clear mucinous cells. The epithelium was focally pseudostratified and presented numerous ciliated cells (Figure 3). In some dilated ducts, the lining epithelium was eroded, and the surrounding connective tissue contained an abundant mixed inflammatory infiltrate (Figure 2). There was no smooth muscle tissue around the cystic ducts.

[FIGURES 1-3 OMITTED]

COMMENT

Brunner gland hamartoma is a rare duodenal lesion, which was first described by Cruveilhier at the end of the 19th century. (1) It is usually discovered in middle-aged adults. (1-3) Half of the patients complain of epigastralgia or gastrointestinal hemorrhage. In the remaining cases, Brunner gland hamartoma is found incidentally during a gastrointestinal endoscopy performed for an unrelated condition. (1-3) The lesion usually presents as a pedunculated polyp located in the first part of the duodenum and measures from 0.7 to 12 cm (average 4 cm). (1-3) It is considered a hamartomatous lesion, characterized by the presence of mature but disorganized tissues, and is found most commonly in the duodenum. (1-3) On microscopic examination, it is composed mainly of lobules of Brunner glands, lined by cylindrical clear mucous cells. They are surrounded by a fibrous adipose tissue containing vessels and nerves. (1-3) In some cases, including the case we report, the adipose tissue represents the major part of the lesion. (2) In most cases, Brunner gland hamartoma contains ducts, often dilated and sometimes branched. (3) These ducts can be surrounded by an inflammatory infiltrate with some lymphoid follicles. (2) Brunner glands are rarely dilated and cystic, but in such cases, they are lined by cuboidal or cylindrical mucinous cells. (3) Our case contained numerous dilated cystic ducts with a lining epithelium rich in ciliated cells. The presence of mucinous cylindrical Brunner gland cells mixed with this ciliated respiratory-type epithelium is in favor of metaplastic changes of Brunner gland duct epithelium. The hypothesis of cystic inclusion of endodermal epithelium from the primitive foregut, as has been described in the esophagus, is unlikely because of the lack of muscularis tissue around ciliated cysts. (4)

The presence of ciliated cells in the gut mucosa is a rare phenomenon. To our knowledge, it has never been reported in the duodenum. Ciliated cells have been described in the esophageal and gastric mucosa in dilated gastric glands around peptic ulcer, gastric dysplasia, or adenocarcinoma. (5,6) In the esophagus, this ciliated epithelium is interpreted as the remnant of the original embryonic endodermal epithelium. (5) In the stomach, it has been interpreted as an adaptive metaplasia of the pyloric epithelium lining the glands, in response to a new environment due to mucus retention. (6)

Despite the presence of prominent mature adipose tissue, our lesion can be distinguished from a duodenal lipoma by the presence of ectopic Brunner gland and dilated ducts. (7) The lack of smooth muscle layer around the submucosal cysts and the presence of predominant adipose tissue in the duodenal polyp enable us to distinguish this lesion from an intestinal duplication. Duodenal duplication cysts are often lined by a duodenal or gastric mucosa. (8)

Brunner gland hamartoma is a benign lesion, which can be treated by limited surgical resection or polypectomy. (1-3) Very few cases of Brunner gland hamartoma have been reported in association with epithelial dysplasia, duodenal adenocarcinoma, and carcinoid tumors. (9,10)

References

(1.) Walden DT, Marcon NE. Endoscopic injection and polypectomy for bleeding Brunner's gland hamartoma: case report and expanded literature review. Gastrointest Endosc. 1998;47:403-407.

(2.) Levine JA, Burgart LJ, Batts KP, Wang KK. Brunner's gland hamartomas: clinical presentation and pathological features of 27 cases. Am J Gastroenterol. 1995; 90:290-304.

(3.) Golan J, Dollberg L, Dollberg M, Farkash T, Rivkin L. Cystic hamartoma of Brunner's glands. Int Surg. 1978;63:173-175.

(4.) Arbona JL, Figueroa Fazzi JG, Mayoral J. Congenital oesophageal cysts: case report and review of literature. Am J Gastroenterol. 1984;79:177-182.

(5.) Rubio CA, Kato Y. Ciliated metaplasia in the gastric mucosa: studies on Japanese patients. Jpn J Cancer Res. 1986;77:282-286.

(6.) Raeburn C. Columnar ciliated epithelium in the adult oesophagus. J Pathol Bacteriol. 1951;58:157-158.

(7.) Imamura K, Fuchigami T, Lida M, et al. Duodenal lipoma: a report of three cases. Gastrointest Endosc. 1983;29:223-224.

(8.) Dave P, Romeu J, Clary S, Rybak B, Messer J. Endoscopic removal of an obstructing duodenal duplication cyst. Endoscopy. 1984;16:75-76.

(9.) Itsuno M, Makiyama K, Omagari K, et al. Carcinoma of duodenal bulb arising from the Brunner's gland. Gastroenterol Jpn. 1993;28:118-125.

(10.) Zanetti G, Casadei G. Brunner's gland hamartoma with incipient ductal malignancy. Tumori. 1981;67:75-78.

Accepted for publication September 26, 2001.

From the Service d'Anatomie Pathologique, Hopital Saint-Antoine, Paris, France (Drs Chatelain, Mourra, and Flejou); Cabinet de Pathologie de Saint-Denis, Reunion, France (Dr Maillet); Service de Chirurgie Digestive et Gynecologique, Clinique Sainte-Clotilde, Reunion, France (Dr Boyer); and Cabinet de Gastroenterologie, Reunion, France (Dr Checkouri).

Reprints: Jean-Francois Flejou, MD, PhD, Service d'Anatomie Pathologique, Hopital Saint-Antoine, 184 Rue du Fg Saint-Antoine, 75571 Paris Cedex 12 (e-mail: [e-mail]).