Gastric Adenomas in Familial Adenomatous Polyposis Are Common, But Subtle, and Have a Benign Course

Abstract

Background: Patients with familial adenomatous polyposis (FAP) are known to have an increased risk for gastric adenomas. The clinical features of gastric adenomas in FAP have not been well characterized, and there is a lack of standardized approaches to the management of these lesions. Aims: To study the endoscopic appearance, risk factors, clinical course, and response to therapy of gastric adenomas in patients with FAP. Methods: We retrospectively reviewed the records of 97 patients with FAP who underwent esophagogastroduodenoscopy (EGD) at Mayo Clinic (Florida, Rochester and Arizona) between 2004 and 2013. Results: Nine patients (9%) had biopsy-proven gastric adenomas. Adenomas were located in the antrum (five patients), in the body and fundus in the setting of background fundic gland polyps (FGP) (three patients), and in the body not associated with FGP (one patient). Adenoma size was 3-40 mm and the number of adenomas per patient ranged from one to 20. Adenomas in the antrum were flat and subtle, whereas those in the gastric body or fundus were polypoid and difficult to differentiate from the cystic FGPs seen in patients with FAP. The performing endoscopists reported difficulty with identifying adenomas, and six patients had at least one EGD within the previous three years where gastric adenomas were not reported. Adenomas were classified as tubular in eight patients and tubulovillous in one patient. High grade dysplasia was noted in one patient. After a median follow-up of 63 months (interquartile range: 20-149 months), no patient in our entire cohort (with or without gastric adenomas) developed gastric cancer. The patients in whom gastric adenoma developed, compared to those without gastric adenoma, were more likely to be younger [36 ± 12 vs. 48 ± 15 years, p = 0.02], have concomitant chronic gastritis [22% vs. 0%, p = 0.008], and have desmoid tumors [5 (56%) vs. 19 (22%), p = 0.04]. Conclusions: Gastric adenomas are not uncommon in patients with FAP and are often difficult to identify endoscopically. Endoscopists should have a high degree of suspicion for gastric adenomas in these patients and a low threshold to biopsy. Given the benign clinical course, recommended initial management is conservative with endoscopic therapy and periodic surveillance.

Gastric tumours in FAP

“…Indeed, a greater proportion of gastric adenoma cases than would normally be expected had a personal or family history of desmoid. Interestingly, Ngamruengphong et al also reported that patients with FAP and a gastric adenoma were significantly more likely to have had a desmoid tumour compared to patients without a history of a gastric adenoma, 5/9 (56%) and 19/88 (22%), respectively [13]. This was comparable to our study's findings.…”

“…Spigelman et al previously reported that patients with gastric adenomas had a higher incidence of severe duodenal polyposis [18]. A more recent study by Ngamruengphong et al failed to show an association between gastric adenomas and duodenal disease in FAP [13].…”

“…2, 3), further impeding the pick-up rate for proximal lesions. Ngamruengphong et al reported a significant adenoma miss rate at endoscopy affecting 6/9 patients [13]. A recent systematic review and metaanalysis reported an endoscopic miss rate for the detection of gastric cancers in a non-FAP population as high as 10%, particularly when lesions were located in the body [24].…”

“…One such study reported upper GI lesions in FAP and detected gastric dysplasia in only 6 of 102 patients studied endoscopically, with a predilection for the antrum [18]. The largest study in the Western world to report gastric adenoma occurrence involved only 9 cases [13]. The aim of this descriptive study was to report the clinical features of gastric adenomas and carcinomas arising in patients with FAP attending our institution.…”

“…It would appear from this small, retrospective study that gastric cancer is not a prominent with FAP is lower in the Western world compared to Asian populations. In the West, gastric adenomas are reported to occur in 2-10% of patients [11][12][13] but ranges between 15-50% in Asian populations [14][15][16][17].…”