A 71-year-old female was referred by her general practitioner for an upper gastrointestinal endoscopy, with 3 months of progressively worsening dysphagia, epigastric pain, nausea and vomiting. She had concurrent weight loss. A trial of pantoprazole had made no improvement. Her symptoms were typically worse postprandially. Her past medical history was significant for ischaemic heart disease, mild emphysema, rheumatoid arthritis, hypothyroidism and hypertension.
Upper gastrointestinal endoscopy showed a large amount of food residue in the stomach. The pylorus was scarred, stenosed and unable to be traversed (Figure 1). Biopsies showed no evidence of malignancy. As she was taking clopidogrel, dilatation was not attempted.
Figure 1: Endoscopic view of the pylorus.
Her proton pump inhibitor dose was increased to 40 mg per day, and she had a repeat endoscopy at 6 weeks. Endoscopic findings were unchanged and biopsies again showed no malignancy. Dilatation was attempted but was unsuccessful. She proceeded to a CT scan of her abdomen, which showed circumferential pyloric wall thickening and small 9 mm gastrohepatic and mesenteric nodes, suspicious for a pyloric neoplasm (Figure 2).
Figure 2: Axial CT. Arrow: thickened pylorus.
Figure 3: Microscopic view of the pylorus showing hyperplasia of the muscularis propria.
She proceeded to surgery for a Billroth II subtotal gastrectomy. Operative findings were of a thickened isolated mass at the pylorus. There was no evidence of infiltrative changes nor of surrounding lymphadenopathy. A subtotal gastrectomy was performed. Her recovery was uncomplicated and post operatively, her symptoms were much improved.
The macroscopic pathological findings were of a 2 cm ill-defined submucosal mass at the level of the pylorus. The serosal and mucosal surfaces were unremarkable. Microscopic sections showed hyperplasia of the muscularis propria in the pyloric region (Figure 2). The presumptive diagnosis was of idiopathic hypertrophic pyloric stenosis.
Idiopathic hypertrophic pyloric stenosis (IHPS) is a disease usually seen in infants. Adult IHPS (AIHPS) is rare, and was first described by Jean Cruveilhier in 1835.1 It is generally classified as either primary or secondary.
AIHPS presents in adult life without any apparent cause, and with no history of infantile vomiting, suggestive of pyloric stenosis of infancy. Microscopically, there is total or segmental hypertrophy of the smooth muscle of the pylorus, without any identifiable underlying disease.2
Secondary hypertrophic pyloric stenosis is as a result of other diseases of the upper gastrointestinal tract, such as peptic ulcer disease, malignancy and inflammatory diseases. Microscopically, there is localised replacement by fibrous tissue, and minimal or no hypertrophy of the muscularis propria.
The aetiology of AIHPS remains unknown. Most authors believe it is likely due to the persistence of a mild infantile form into adult life.3 Infantile and adult IHPS have a similar anatomical and histological appearance.
Diagnosis is based upon history, clinical and radiological findings and endoscopic appearance. The predominant symptom is postprandial abdominal pain and distension. The discomfort tends to be relieved by vomiting. Weight loss and anorexia are common. Unlike infantile IHPS, an abdominal mass is not usually palpable. It may be mistaken radiologically and endoscopically for a gastric gastrointestinal stromal tumour, or a diffuse infiltrating adenocarcinoma given the normal overlying mucosa.
Endoscopically, the pylorus is fixed, narrowed and has a smooth border. Its appearance has been described as the “cervix sign” by Schuster and Smith4. Biopsies should always be taken, however they are frequently normal as the gastric mucosa is unaffected and therefore submucosal malignancies cannot be excluded. An endoscopic ultrasound and fine-needle aspirate or core biopsy may be performed, predominantly to exclude other submucosal tumours. Biopsies, however, may be inconclusive and currently there are no clear guidelines on their use. Dilatation can be performed, but results are usually temporary and recurrence high.
Surgery is indicated in the treatment of AIHPS. Partial gastrectomy, gastroenterostomy, pyloromyotomy and pyloroplasty have all been proposed as treatments.2, 3, 5 In many cases, malignancy cannot be excluded, therefore gastric resection with either Billroth I or II reconstruction may be performed, and is preferred by most clinicians. Pyloroplasty is generally favoured over pyloromyotomy, due to the risk of mucosal laceration and subsequent diverticulum formation with pyloromyotomy. Pyloroplasty can be successfully performed laparoscopically.5
AIHPS is a rare condition with less than 300 case reports in the literature. Its aetiology is unclear, but may be an attenuated form of infantile pyloric stenosis. It may be treated endoscopically, however most patients proceed to surgery and a partial gastrectomy is preferred by most clinicians.