Brunner Gland Hamartoma

Brunner gland hamartoma (Brunner gland adenoma or hyperplasia) is a benign, localised overgrowth of Brunner glands in the duodenum, forming a polypoid submucosal lesion, usually in the bulb or the proximal second part.

It represents about 5% to 10% of benign duodenal tumours. Peak age is 40 to 60 years, with equal sex distribution.

Types are diffuse nodular hyperplasia, circumscribed nodular hyperplasia and solitary hamartoma or polyp (the commonest, 1 to 3 cm, rarely up to 12 cm).

Associations are hyperacidity, Helicobacter pylori infection and chronic renal failure.

Essentially benign; rare reports of dysplasia and adenocarcinoma.

Pathophysiology.

Lobules of mature Brunner glands with ducts, adipose tissue, smooth muscle and lymphoid cells form the lesion.

Most are asymptomatic. Larger lesions cause gastrointestinal bleeding with anaemia, upper abdominal pain, nausea, obstruction, intussusception, obstructive jaundice or pancreatitis (ampullary involvement).

Endoscopy shows a smooth, sessile or pedunculated polyp, occasionally ulcerated. Forceps biopsy is often non-diagnostic because the lesion is submucosal. Endoscopic ultrasound shows a hyperechoic or mixed echo mass in the second to third layer. CT shows a well defined lesion. Excision biopsy gives the diagnosis.

Differential diagnosis.

• Duodenal adenoma.
• Neuroendocrine tumour.
• Gastrointestinal stromal tumour.
• Ectopic pancreas.
• Heterotopic gastric mucosa.
• Lipoma.

Small asymptomatic lesions can be observed. Remove symptomatic lesions: endoscopic snare polypectomy for pedunculated polyps (over 3 cm needs experienced operators), mucosal resection for sessile lesions, and surgical excision for lesions over 4 cm, deep lesions or failed endoscopy.

• Omeprazole: 20 to 40 mg orally once daily for 4 to 8 weeks for hyperacidity and Helicobacter pylori negative disease; maximum 40 mg daily for this use; monitor symptoms; reduce to 20 mg daily in severe hepatic impairment.
• Helicobacter pylori eradication if positive (bismuth quadruple therapy): bismuth subsalicylate 524 mg, tetracycline 500 mg and metronidazole 500 mg, each orally four times daily, with omeprazole 20 mg orally twice daily, for 14 days; maximum tetracycline 2 g daily and metronidazole 2 g daily; monitor for neuropathy, nausea and adherence; avoid tetracycline in pregnancy and reduce metronidazole in severe hepatic impairment; test for cure at least 4 weeks after treatment.

Monitoring. Endoscopy at 12 months after incomplete resection; observation lesions at 1 to 2 years.

Referral and escalation. Advanced endoscopy or surgery for lesions over 3 cm, bleeding or obstruction.