Brunner’s gland hamartoma presenting as gastric outlet obstruction: unusual presentation and review of literature

Introduction

Brunner’s gland hamartoma (or Brunneroma) is an uncommon tumour with an incidence of < 0.01%, accounting for approximately 5–10% of benign duodenal tumours. Usually asymptomatic, it may manifest occasionally with duodenal obstruction or upper gastrointestinal haemorrhage and rarely with biliary fistulation, cholestatic jaundice and intussusception. It may be associated with uraemia and chronic pancreatitis. The diagnosis is usually confirmed by imaging studies and upper gastrointestinal endoscopy. Surgical excision or endoscopic resection is preferred for symptomatic large hamartomas.

Case report

A 45-year man presented at the hepato-pancreato-biliary clinic of our institute with chief complaints of upper abdominal pain for three months, of acute initial onset, intermittent, colicky in nature and radiating to the back, associated with non-bilious, projectile vomiting. There was no history of fever, jaundice, weight loss or loss of appetite. Bladder and bowel habit were normal. A history of chronic alcoholism was present. Vital signs were stable. General physical examination was unremarkable. The abdomen was soft with tenderness present in epigastrium and right hypochondrium region. There was no palpable abdominal mass or organomegaly. There was no ascites noted. Bowel sounds were normal. There was no gastric splash. Digital rectal examination was unremarkable. There was no gastric splash.Routine blood tests, including full blood cell count and biochemistry, showed no abnormality except raised amylase (443 U/L, normal range = 23–85 U/L) and lipase (569 U/L, normal range = 0–160 U/L) levels. Urine examination showed no paradoxical aciduria. Abdominal ultrasonography revealed an area of high periportal echogenicity.

Abdominal computed tomography (CT) scan with pancreatic protocol (Figure 1) suggested a large circumferential heterogeneously enhancing soft-tissue mass in the second part of duodenum, with a maximum thickness of 21 mm and length of 34 mm leading to complete duodenal narrowing. Medially the lesion showed indistinct fat planes with a ‘double duct sign’ (common bile duct = 10 mm, main pancreatic duct = 9 mm) and moderate intrahepatic biliary radical dilatation); no invasion of the hepatic flexure of the colon was noted. Subcentrimetric mesenteric and retroperitoneal lymphadenopathy was seen. Tumour markers were within normal ranges (CA 19-9: 12.9 U/mL, CEA: 0.47 ng/mL, CA125: < 2 U/L). Endoscopy revealed a proliferative mass in the second part of the duodenum. Biopsy showed no evidence of malignancy. OPEN IN VIEWER

In view of persisting symptoms, surgical exploration was carried out. The tumour was found to have a broad-based attachment to the duodenal wall with invasion of the pancreatic head, precluding a local excision (Figure 2). Consequently, a pancreatico-duodenectomy was performed; histopathology of the excised specimen was suggestive of a Brunner’s gland hamartoma (basally located smooth regular nuclei) with chronic pancreatitis. There was splaying of muscle layer by Brunner glands along with lymphocytic infiltrate within the splayed muscle fibres (Figure 3). OPEN IN VIEWER

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Figure 3.

Section examined shows hyperplastic Brunner’s gland with basally located smooth regular nuclei. There is splaying of muscle layer by Brunner glands along with lymphocytic infiltrate within the splayed muscle fibres and peri glandular location.

The patient provided consent that his clinical images and other clinical information be reported in this journal.

Discussion

Brunner’s glands are mucin-secreting acinar glands situated in the duodenal deep mucosa and submucosa and secrete alkaline fluid containing mucus, pepsinogen and urogastrone in response to acid stimulation. This alkaline fluid forms a coating over the duodenal mucosa and protects it from acid chime. The glands were described by Swiss anatomist Johann Conrad Brunner in 1688 and named after him. An adenoma of Brunner’s glands was first reported in 1835.^1,2 It is a benign hamartoma, caused by proliferation of acinar glands. Features such as lack of encapsulation, regular acini, smooth muscle and adipose tissue, mucosal glands and lack of any cell atypia are suggestive of hamartomas, rather than neoplasia. Immunohistochemistry shows an increased expression of p53 antigen in these lesions. ³ They account for 5–10% of benign duodenal tumours. Brunner gland adenomas have been reported in a variety of age groups, varying from infants to 80 years but are most commonly seen in the 40–60-year age group, without any gender predominance. They are most commonly found at the junction of first and second part of duodenum, more precisely the duodenal bulb.

The exact aetiology of Brunner gland hamartoma is not known. Various factors supposed to be associated include hyperchlorhydria, Helicobacter pylori infection, chronic inflammation, uraemia and chronic pancreatitis. Hyperchlorhydria may indeed be a stimulating factor causing hyperplasia of acinar glands so as to neutralise the acidic chime.^3,4

Brunner’s gland hyperplasia has been classified by Feyrter as: diffuse nodular hyperplasia confined to the mucosa with multiple sessile projections spread throughout the duodenum (Type 1); limited to the duodenal bulb as circumscribed nodular hyperplasia, usually < 1 cm in size (Type 2, the most common type); and adenomatous hyperplasia (also known as Brunner’s gland hamartoma or adenoma), which generally present as a single polypoid lesion, with its size in the range of 0.7–12 cm, with a mean of 4 cm (Type 3). ⁵

Usually patients with Brunner gland hamartoma are asymptomatic and it is found incidentally, unless it is causing obstructing symptoms. Surgical or endoscopic resection is preferred.