Susanne van Eeden

Hyperplastic Polyps and Sessile Serrated Adenomas as a Phenotypic Expression of MYH-Associated Polyposis

BACKGROUND & AIMS MYH-associated polyposis (MAP) is a disorder caused by a bi-allelic germline MYH mutation, characterized by multiple colorectal adenomas. These adenomas typically harbor G:C-->T:A transversions in the APC and K-ras genes caused by MYH deficiency. Occasional hyperplastic polyps (HPs) have been described in MAP patients but a causal relationship has never been investigated. We examined the presence of HPs and sessile serrated adenomas (SSAs) in 17 MAP patients and studied the occurrence of G:C-->T:A transversions in the APC and K-ras gene in these polyps. METHODS MAP patients were analyzed for the presence of HPs/SSAs. APC-mutation cluster region and K-ras codon 12 mutation analysis was performed in adenomas (n = 22), HPs (n = 63), and SSAs (n = 10) from these patients and from a control group of sporadic adenomas (n = 17), HPs (n = 24), and SSAs (n = 17). RESULTS HPs/SSAs were detected in 8 of 17 (47%) MAP patients, of whom 3 (18%) met the criteria for hyperplastic polyposis syndrome. APC mutations were detected only in adenomas and comprised exclusively G:C-->T:A transversions. K-ras mutations were detected in 51 of 73 (70%) HPs/SSAs in MAP patients, compared with 7 of 41 (17%) sporadic HPs/SSAs in the control group (P < .0001). In HPs/SSAs, 48 of 51 (94%) K-ras mutations showed G:C-->T:A transversions, compared with 2 of 7 (29%) sporadic HPs/SSAs in the control group (P < .0001). CONCLUSIONS HPs and SSAs are a common finding in MAP patients. The detection of almost exclusively G:C-->T:A transversions in the K-ras gene of HPs/SSAs strongly suggests that these polyps are related causally to MYH deficiency. This implies that distinct pathways, that is, APC-gene related in adenomas and nonrelated in HPS/SSAs, appear to be operational in MAP.

Endoscopic features of sessile serrated adenomas: validation by international experts using high-resolution white-light endoscopy and narrow-band imaging

BACKGROUND Sessile serrated adenomas/polyps (SSAs/Ps) are premalignant lesions susceptible to being easily overlooked by endoscopists. A detailed description of the endoscopic appearance of SSAs/Ps might help endoscopists to recognize these lesions to improve the effectiveness of colonoscopy. OBJECTIVE To identify various endoscopic features of SSAs/Ps using high-resolution white-light endoscopy (HR-WLE) and narrow-band imaging (NBI). DESIGN Retrospective image evaluation study. SETTING Single tertiary referral center. PATIENTS Forty-5 patients with serrated polyposis syndrome undergoing surveillance colonoscopies. INTERVENTION HR-WLE and NBI images of 150 polyps (50 SSAs/Ps, 50 hyperplastic polyps [HPs], and 50 adenomas) were systematically assessed by 5 experts using various endoscopic descriptors. MAIN OUTCOME MEASUREMENTS The prevalence of specific endoscopic features observed in SSAs/Ps versus HPs. RESULTS Multivariate analysis demonstrated that indistinct borders (OR, 3.11; 95% CI, 1.57-6.15) and a cloud-like surface (OR, 2.65; 95% CI, 1.21-5.78) were associated with SSA/P histology on HR-WLE. On NBI, a cloud-like surface (OR, 4.91; 95% CI, 2.42-9.97), indistinct borders (OR, 2.38; 95% CI, 1.14-4.96), irregular shape (OR, 3.17; 95% CI, 1.59-6.29), and dark spots inside the crypts (OR, 2.05; 95% CI, 1.02-4.11) were found to be endoscopic predictors of SSA/P histology. The sensitivity, specificity, and accuracy of NBI for differentiating serrated polyps containing either none or all 4 endoscopic SSA/P features were, respectively, 89%, 96%, and 93%. LIMITATIONS Retrospective, image evaluation analysis. CONCLUSIONS The current study demonstrates that SSAs/Ps possess several specific endoscopic features compared with HPs. Recognition of these characteristics might assist endoscopists in the differentiation of these lesions and could possibly facilitate endoscopic detection of these rather subtle lesions.

Clinical evaluation of endoscopic trimodal imaging for the detection and differentiation of colonic polyps.

BACKGROUND & AIMS Endoscopic trimodal imaging (ETMI) incorporates high-resolution endoscopy (HRE) and autofluorescence imaging (AFI) for adenoma detection, and narrow-band imaging (NBI) for differentiation of adenomas from nonneoplastic polyps. The aim of this study was to compare AFI with HRE for adenoma detection and to assess the diagnostic accuracy of NBI for differentiation of polyps. This was a randomized trial of tandem colonoscopies. The study was performed at the Academic Medical Center in Amsterdam. METHODS One hundred patients underwent colonoscopy with ETMI. Each colonic segment was examined twice for polyps, once with HRE and once with AFI, in random order per patient. All detected polyps were assessed with NBI for pit pattern and with AFI for color, and subsequently removed. Histopathology served as the gold standard for diagnosis. The main outcome measures of this study were adenoma miss-rates of AFI and HRE, and diagnostic accuracy of NBI and AFI for differentiating adenomas from nonneoplastic polyps. RESULTS Among 50 patients examined with AFI first, 32 adenomas were detected initially. Subsequent inspection with HRE identified 8 additional adenomas. Among 50 patients examined with HRE first, 35 adenomas were detected initially. Successive AFI yielded 14 additional adenomas. The adenoma miss-rates of AFI and HRE therefore were 20% and 29%, respectively (P = .351). The sensitivity, specificity, and overall accuracy of NBI for differentiation were 90%, 70%, and 79%, respectively; corresponding figures for AFI were 99%, 35%, and 63%, respectively. CONCLUSIONS The overall adenoma miss-rate was 25%; AFI did not significantly reduce the adenoma miss-rate compared with HRE. Both NBI and AFI had a disappointing diagnostic accuracy for polyp differentiation, although AFI had a high sensitivity.

Combining Autofluorescence Imaging and Narrow-Band Imaging for the Differentiation of Adenomas from Non-Neoplastic Colonic Polyps Among Experienced and Non-Experienced Endoscopists

OBJECTIVES:Endoscopic tri-modal imaging incorporates high-resolution white-light endoscopy (HR-WLE), narrow-band imaging (NBI), and autofluorescence imaging (AFI). Combining these advanced techniques may improve endoscopic differentiation between adenomas and non-neoplastic polyps. In this study, we aimed to assess the interobserver variability and accuracy of HR-WLE, NBI, and AFI for polyp differentiation and to evaluate the combined use of AFI and NBI.METHODS:First, still images of 50 polyps (22 adenomas; median 3 mm) were randomly displayed to three experienced and four non-experienced endoscopists. All HR-WLE and NBI images were scored for Kudo classification and AFI images for color. Second, the combined AFI and NBI images were assessed using a newly developed algorithm by six additional non-experienced endoscopists.RESULTS:The outcomes measured were interobserver agreement and diagnostic accuracy using histopathology as reference standard. Experienced endoscopists had better interobserver agreement for NBI (κ=0.77) than for AFI (κ=0.33), whereas non-experienced endoscopists had better agreement for AFI (κ=0.58) than for NBI (κ=0.33). The accuracies of HR-WLE, NBI, and AFI among experienced endoscopists were 65, 70, and 74, respectively. Figures among non-experienced endoscopists were 57, 63, and 77. The algorithm was associated with a significantly higher accuracy of 85% among all observers (P<0.023). These figures were confirmed in the second evaluation study.CONCLUSIONS:Non-experienced endoscopists have better interobserver agreement and accuracy for AFI than for HR-WLE or NBI, indicating that AFI is easier to use for polyp differentiation in non-experienced setting. The newly developed algorithm, combining information of AFI and NBI together, had the highest accuracy and obtained equal results between experienced and non-experienced endoscopists.

Hyperplastic polyposis syndrome: a pilot study for the differentiation of polyps by using high-resolution endoscopy, autofluorescence imaging, and narrow-band imaging

BACKGROUND Endoscopic differentiation and removal of potentially premalignant sessile serrated adenomas (SSAs) may be important steps in preventing the development of colorectal cancer in hyperplastic polyposis syndrome (HPS). OBJECTIVE To assess the value of high-resolution endoscopy, autofluorescence imaging (AFI), and narrow-band imaging (NBI) for differentiating polyps in HPS. DESIGN A prospective polyp series. SETTING Single tertiary referral center. PATIENTS AND INTERVENTIONS Seven patients with HPS underwent colonoscopy with endoscopic trimodal imaging, which incorporates high-resolution endoscopy, AFI, and NBI in 1 system. All detected polyps were analyzed with AFI for color and with NBI for Kudo pit pattern and vascular pattern intensity. MAIN OUTCOME MEASUREMENTS The accuracy, sensitivity, and specificity of AFI and NBI in differentiating detected polyps were determined by using histology as the criterion standard. RESULTS A total of 19 hyperplastic polyps (HPs), 32 SSAs, and 15 adenomas were detected. For differentiating SSAs from HPs, AFI color, Kudo pit pattern, and vascular pattern intensity resulted in a diagnostic accuracy of 55%, 55%, and 52%, respectively. For differentiating adenomas from HPs, the accuracy was 65%, 94%, and 90%, respectively. Macroscopically, the combination of a size of 3 mm or larger and a proximal location resulted in the highest accuracy (76%) for differentiating SSAs from HPs. LIMITATION Small sample size. CONCLUSION Endoscopic differentiation between HPs and SSAs by using endoscopic trimodal imaging proved unsatisfactory. Differentiation of adenomas from HPs was possible with NBI but not with AFI.

A Serrated Colorectal Cancer Pathway Predominates over the Classic WNT Pathway in Patients with Hyperplastic Polyposis Syndrome

Hyperplastic polyposis syndrome (HPS) is characterized by the presence of multiple colorectal serrated polyps and is associated with an increased colorectal cancer (CRC) risk. The mixture of distinct precursor lesion types and malignancies in HPS provides a unique model to study the canonical pathway and a proposed serrated CRC pathway in humans. To establish which CRC pathways play a role in HPS and to obtain new support for the serrated CRC pathway, we assessed the molecular characteristics of polyps (n = 84) and CRCs (n = 19) in 17 patients with HPS versus control groups of various sporadic polyps (n = 59) and sporadic microsatellite-stable CRCs (n = 16). In HPS and sporadic polyps, APC mutations were exclusively identified in adenomas, whereas BRAF mutations were confined to serrated polyps. Six of 19 HPS CRCs (32%) were identified in a serrated polyp. Mutation analysis performed in the CRC and the serrated component of these lesions showed identical BRAF mutations. One HPS CRC was located in an adenoma, both components harboring an identical APC mutation. Overall, 10 of 19 HPS CRCs (53%) carried a BRAF mutation versus none in control group CRCs (P = 0.001). Six BRAF-mutated HPS CRCs (60%) were microsatellite unstable owing to MLH1 methylation. These findings provide novel supporting evidence for the existence of a predominant serrated CRC pathway in HPS, generating microsatellite-stable and microsatellite-instable CRCs.

Incidence of Colonic Neoplasia in Patients With Serrated Polyposis Syndrome Who Undergo Annual Endoscopic Surveillance

BACKGROUND & AIMS Patients with serrated polyposis syndrome (SPS) are advised to undergo endoscopic surveillance for early detection of polyps and prevention of colorectal cancer (CRC). The optimal surveillance and treatment regimen is unknown. We performed a prospective study to evaluate a standardized endoscopic treatment protocol in a large cohort of patients with SPS. METHODS We followed a cohort of patients with SPS who received annual endoscopic surveillance at the Academic Medical Centre in Amsterdam, The Netherlands from January 2007 through December 2012. All patients underwent clearing colonoscopy with removal of all polyps ≥3 mm. After clearance, subsequent follow-up colonoscopies were scheduled annually. The primary outcomes measure was the incidence of CRC and polyps. Secondary outcomes were the incidence of complications and the rate of preventive surgery. RESULTS Successful endoscopic clearance of all polyps ≥3 mm was achieved in 41 of 50 (82%) patients. During subsequent annual surveillance, with a median follow-up time of 3.1 years (interquartile range, 1.5-4.3 years), CRC was not detected. The cumulative risks of detecting CRC, advanced adenomas, or large (≥10 mm) serrated polyps after 3 surveillance colonoscopies were 0%, 9%, 34%, respectively. Twelve patients (24%) were referred for preventive surgery; 9 at initial colonoscopy and 3 during surveillance. Perforations or severe bleeding did not occur. CONCLUSIONS Annual surveillance with complete removal of all polyps ≥3 mm with timely referral of selected high-risk patients for prophylactic surgery prevents development of CRC in SPS patients without significant morbidity. Considering the substantial risk of polyp recurrence, close endoscopic surveillance in SPS seems warranted. www.trialregister.nl ID NTR2757.

Comparison between serology and histology in the diagnosis of advanced gastric body atrophy: a study in a Dutch primary community.

Goals To assess serologically diagnosed gastric body atrophy (GBA) by histology in a sample of the general population. Background GBA is a precursor lesion in gastric cancer. Data on GBA in a primary health care community in the Netherlands have not been reported. Study Thirty-four subjects of 997 consecutive adults from a Dutch family practice had serologic GBA, according to hypergastrinemia (>100 ng/L), hypopepsinogenemia A (<17 μg/L), and a low pepsinogen A/C ratio (<1.6). Two years later, 25 subjects of this group, agreed in serologic retesting and gastroscopy with biopsies for histologic assessment according to the Sydney system. Results At serologic retesting, 20 of 25 subjects again fulfilled the serologic criteria of GBA. Histologic examination of the corpus biopsies showed advanced GBA in 18 subjects (75%) of 24 (1 subject had no corpus biopsies) and 17 of 19 (89%) subjects with repeated positive serology. After disclosure of serology results, reexamination of the biopsies revealed GBA also in the 2 patients with initially insufficient evidence of GBA, giving a concordance of 100% (19/19). One subject with normal serum gastrin at retesting had both antral and body atrophy giving a concordance between serologic and histologic GBA of 95% (19/20). No adenomatous polyps, tumors, or dysplastic alterations were found. Conclusions Identification by serology of asymptomatic patients with advanced GBA in primary care is adequately possible and useful in selecting for endoscopy.

The role of high-resolution endoscopy and narrow-band imaging in the evaluation of upper GI neoplasia in familial adenomatous polyposis.

BACKGROUND The Spigelman classification stratifies cancer risk in familial adenomatous polyposis (FAP) patients with duodenal adenomatosis. High-resolution endoscopy (HRE) and narrow-band imaging (NBI) may identify lesions at high risk. OBJECTIVE To compare HRE and NBI for the detection of duodenal and gastric polyps and to characterize duodenal adenomas harboring advanced histology with HRE and NBI. DESIGN Prospective, nonrandomized, comparative study. Retrospective image evaluation study. SETTING Tertiary-care center. PATIENTS Thirty-seven FAP patients undergoing surveillance upper endoscopies. INTERVENTION HRE endoscopy was followed by NBI. The number of gastric polyps and Spigelman staging were compared. Duodenal polyp images were systematically reviewed in a learning and validation phase. MAIN OUTCOME MEASUREMENTS Number of gastric and duodenal polyps detected by HRE and NBI and prevalence of specific endoscopic features in duodenal adenomas with advanced histology. RESULTS NBI did not identify additional gastric polyps but detected more duodenal adenomas in 16 examinations, resulting in upgrades of the Spigelman stage in 2 cases (4.4%). Pictures of 168 duodenal adenomas (44% advanced histology) were assessed. In the learning phase, 3 endoscopic features were associated with advanced histology: white color, enlarged villi, and size ≥1 cm. Only size ≥1 cm was confirmed in the validation phase (odds ratio 3.0; 95% confidence interval, 1.2-7.4). LIMITATIONS Nonrandomized study, scant number of high-grade dysplasia adenomas. CONCLUSION Inspection with NBI did not lead to a clinically relevant upgrade in the Spigelman classification and did not improve the detection of gastric polyps in comparison with HRE. The only endoscopic feature that predicted advanced histology of a duodenal adenoma was size ≥1 cm.

Ductuloinsular tumors of the pancreas: endocrine tumors with entrapped nonneoplastic ductules.

Rare pancreatic neoplasms have been reported that show both endocrine and exocrine differentiation in the neoplastic components. In addition, pancreatic endocrine tumors may contain small, cytologically bland ductules intimately admixed with the endocrine component. It was recently suggested that these ductules represent an intrinsic part of the tumor, ie, that the ductules are neoplastic, and the term “ductulo-insular tumors of the pancreas” was proposed. In the present study, the nature of the ductular component of 16 cases of ductule-containing pancreatic endocrine tumors was investigated at the molecular level. Molecular genetic changes often present in ductal pancreatic neoplasms were not found by immunohistochemistry for DPC4, p53, and ERBB2 and by sequence analysis of KRAS codon 12. An X-chromosome inactivation clonality assay of one such tumor from a female patient indicated that the neuroendocrine component was monoclonal, contrasting with the ductular component that was polyclonal. The lymph node and liver metastases from three patients only contained the neuroendocrine component, and no ductules were observed. Although certain morphologic features of ductule-containing endocrine tumors are reminiscent of the embryonic development of the human pancreas, none of the tumors expressed PDX-1, a transcription factor essential in pancreatic organ development. Based on our results, it is suggested that the ductular component occasionally found in pancreatic endocrine tumors is the result of entrapment of preexisting nonneoplastic ductules and that the tumors are otherwise not distinctive from conventional pancreatic endocrine tumors. Although the phenomenon is rare, it is important to recognize and to distinguish these tumors from true mixed ductal-endocrine neoplasms, which are generally more clinically aggressive. “Pancreatic endocrine tumors with entrapped ductules” would be the preferred nomenclature since it better reflects the nonneoplastic nature of the ductules.