Eui Gon Youk

Traditional serrated adenoma of the colorectum: clinicopathologic implications and endoscopic findings of the precursor lesions.

OBJECTIVES To investigate the clinicopathologic and endoscopic features of precursor lesions associated with traditional serrated adenomas (TSAs). METHODS Mutation studies for BRAF, KRAS, PIK3CA, and EGFR and immunohistochemical staining for Ki-67 were performed on 107 TSAs from 104 patients. RESULTS Nondysplastic hyperplastic polyp (HP) or sessile serrated adenoma/polyp (SSA/P) precursor lesions were found in 56 (52.3%) TSAs, among which 32 (57.1%) cases showed a flat-elevated lesion with a type II pit pattern during endoscopy. TSAs with an SSA/P precursor lesion were usually found in the proximal colon, while TSAs with an HP or with no precursor lesion were mainly located in the distal colon and rectum (P < .001). TSAs with a precursor lesion showed a lower frequency of conventional epithelial dysplasia and KRAS mutation as well as a higher frequency of BRAF mutation compared with those with no precursor lesion (P = .002, P < .001, and P < .001, respectively). CONCLUSIONS A significant proportion of HP or SSA/P precursor lesions accompanied by TSAs can be detected by endoscopy based on both their flat-elevated growth and type II pit patterns. The heterogeneity of TSAs in terms of clinicopathologic and molecular features correlated with the status or type of precursor lesions.

Magnesium citrate with a single dose of sodium phosphate for colonoscopy bowel preparation.

AIM To evaluate the efficacy and acceptability of magnesium citrate and a single dose of oral sodium phosphate (45 mL) solution for morning colonoscopy bowel preparation. METHODS A total of 159 patients were randomly assigned to receive two split doses of 90 mg of sodium phosphate (Group I, n = 79) or magnesium citrate (250 mL, the day before the procedure) followed by 45 mL of sodium phosphate (the day of procedure, Group II, n = 80). The quality of bowel cleansing and the acceptability of each regimen were compared, including the satisfaction, taste, willing to repeat and adverse effects of each regimen. RESULTS The quality of bowel cleansing of Group II was as good as that of Group I (An Aronchick scale score of good or excellent: 70.9% vs 81.0%, respectively, P = 0.34; the Ottawa system score: 4.4 ± 2.6 vs 3.8 ± 3.0, respectively, P = 0.76). There was no statistically significant difference between both groups with regard to acceptability, including the satisfaction, taste and willingness to repeat the regimen. A significantly greater number of older patients (over 65 years old) in Group II graded the overall satisfaction as satisfactory (48.1% vs 78.1%, respectively; Group I vs Group II, P = 0.01). There were no significant adverse reactions. CONCLUSION Magnesium citrate and a single dose of sodium phosphate was as effective and tolerable as the conventional sodium phosphate regimen and is a satisfactory option.

Can endoscopic submucosal dissection technique be an alternative treatment option for a difficult giant (≥ 30 mm) pedunculated colorectal polyp?

BACKGROUND: Snare polypectomy of a giant pedunculated colorectal polyp is sometimes technically demanding, and, therefore, piecemeal resection is inevitable, despite the relative risk of invasive cancer and postpolypectomy bleeding. OBJECTIVE: The aim of this study was to evaluate the efficacy and safety of endoscopic submucosal dissection in comparison with conventional snare polypectomy for giant pedunculated polyps DESIGN AND SETTINGS: We retrospectively reviewed the clinical outcomes and complications of endoscopic polypectomy for giant pedunculated polyps from October 2006 to November 2011. PATIENTS: All the patients who underwent endoscopic submucosal dissection (n = 23) or snare polypectomy (n = 20) for pedunculated polyps ≥3 cm were enrolled consecutively. In the case of a giant pedunculated polyp with 1) poor visualization of the stalk, 2) technical difficulties in snare positioning for en bloc resection, or 3) need for trimming of the head, we did not attempt piecemeal snare polypectomy, and we performed endoscopic submucosal dissection instead. (These were arbitrarily defined as “difficult” giant pedunculated polyps.) MAIN OUTCOME MEASURES: Data on the patient’s demography, endoscopic and histopathologic findings, clinical outcomes, and complications were analyzed. RESULTS: Among the 43 giant pedunculated polyps, 23 polyps were defined as “difficult” polyps and were removed with endoscopic submucosal dissection. Subpedunculated (stalk <1 cm) type was more common in the “difficult” polyp group (p = 0.01). The overall incidence of cancer was 18.6% (8/43). En bloc resection rates were 100% (23/23) in the endoscopic submucosal dissection group and 90% (18/20) in the snare polypectomy group. The procedure times of snare polypectomy and endoscopic submucosal dissection group did not differ significantly (41.7 ± 13.7 minutes vs 44.9 ± 35.6 minutes, p = 0.70). Postpolypectomy bleeding was noted in 1 case (4.3%) in the endoscopic submucosal dissection group and in 3 cases (15%) in the snare polypectomy group. CONCLUSIONS: Endoscopic submucosal dissection, as well as the snare polypectomy for giant pedunculated polyps, appeared to be effective without major complications and can be an alternative option to achieve en bloc resection, particularly for difficult cases, such as giant subpedunculated polyps.

Pedunculated serrated polyp with histologic features of sessile serrated adenoma: a clinicopathologic and molecular study.

In this study, we describe a previously undescribed pedunculated serrated polyp of the colon showing typical features of sessile serrated adenoma/polyp (SSA/P). All polyps were pedunculated, located in the proximal colon, small in size, and occurred in elderly patients. Histologically, the polyps showed typical features of SSA/P in the basal crypts with irregular, asymmetric expression of Ki-67. All polyps showed the BRAF-V600E mutation. The cells in the polyps did not show obvious cytologic dysplasia, prominent serration, or diffuse cytoplasmic eosinophilia with any occurrence of the so-called “ectopic crypt formation.” We consider pedunculated serrated polyp showing features of SSA/P as a previously undescribed form of serrated adenoma/polyp in the spectrum of serrated neoplasia, which might represent a pedunculated variant of SSA/P or a precursor lesion of proximally located traditional serrated adenomas in the earliest stage.

Endoscopic submucosal dissection for nonpedunculated submucosal invasive colorectal cancer: is it feasible?

Background/aims There have been no definite indications for additional surgical resection after endoscopic submucosal dissection (ESD) of submucosal invasive colorectal cancer (SICC). The aims of this study were to evaluate the feasibility of ESD for nonpedunculated SICC and to determine the need for subsequent surgery after ESD. Patients and methods A total of 150 patients with nonpedunculated SICC in resected specimens after ESD were analyzed. Among them, 75 patients underwent subsequent surgery after ESD. Clinical outcomes of ESD and histopathological risk factors for lymph node (LN) metastasis were evaluated. Results The en-bloc resection and complete resection (R0) rates of ESD were 98% (147/150) and 95.3% (143/150), respectively. None of the patients had delayed bleeding after ESD. Perforations occurred in seven patients (4.7%), which were successfully treated by endoscopic clipping. After subsequent surgery for 75 patients, LN metastases were found in 10 cases (13.3%). The incidence of LN metastasis was significantly higher in tumors featuring submucosal invasion of at least 1500 &mgr;m, lymphovascular invasion, and tumor budding. Multivariate analysis showed that lymphovascular invasion (P=0.034) and tumor budding (P=0.015) were significantly associated with LN metastasis. Among the 150 patients, no local recurrence or distant metastasis was detected, except one patient with risk factors and who refused subsequent surgery, during the overall median follow-up of 34 months (range, 5–63 months). Conclusion ESD is feasible and may be considered as an alternative treatment option for carefully selected cases of nonpedunculated SICC, provided that the appropriate histopathological curative criteria are fulfilled in completely resectable ESD specimens.

Lymph node size is not a reliable criterion for predicting nodal metastasis in rectal neuroendocrine tumours.

The study was designed to assess the correlation between lymph node (LN) size and LN metastasis in patients with rectal neuroendocrine tumours (NETs).

Solitary myofibroma of the sigmoid colon: case report and review of the literature

A 58-year-old woman presented with a solitary myofibroma that arose in the sigmoid colon. Computed tomography revealed a highly enhanced intramural mass (1.3-cm maximum diameter) in the proximal sigmoid colon. Histologically, the tumor exhibited a biphasic growth pattern, which comprised haphazardly arranged, interwoven fascicles of plump, myoid-appearing spindle cells with elongated nuclei and abundant eosinophilic cytoplasm, and more cellular areas of primitive-appearing polygonal cells that were arranged in a hemangiopericytomatous pattern. The tumor cells were positive for smooth muscle actin (SMA), and negative for desmin, h-caldesmon, CD34, cytokeratin, S100 protein, and CD117. The Ki-67 labeling index was not high (up to 7%). Based on these histologic and immunohistochemical features, our patient was diagnosed with a myofibroma of the sigmoid colon. The presence of solitary myofibroma in the intestine of an adult requires attention to avoid misdiagnosis as a more aggressive mesenchymal tumor.Virtual SlidesThe virtual silde(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2096403796957687

Reappraisal of hMLH1 promoter methylation and protein expression status in the serrated neoplasia pathway

The aim of this study was to determine whether human mutL homologue 1 (hMLH1) inactivation precedes the progression of sessile serrated lesion (SSL) into SSL with cytological dysplasia (SSL/D) and to define the histological stage at which promoter methylation and inactivation of hMLH1 occur.

Clinical impact of atypical endoscopic features in rectal neuroendocrine tumors.

AIM To validate the association between atypical endoscopic features and lymph node metastasis (LNM). METHODS A total of 247 patients with rectal neuroendocrine tumors (NETs) were analyzed. Endoscopic images were reviewed independently by two endoscopists, each of whom classified tumors by sized and endoscopic features, such as shape, color, and surface change (kappa coefficient 0.76 for inter-observer agreement). All of patients underwent computed tomography scans of abdomen and pelvis for evaluation of LNM. Univariate and multivariate analyses were performed to identify the factors associated with LNM. Additionally, the association between endoscopic atypical features and immunohistochemical staining of tumors was analyzed. RESULTS Of 247 patients, 156 (63.2%) were male and 15 (6.1%) were showed positive for LNM. On univariate analysis, tumor size (P < 0.001), shape (P < 0.001), color (P < 0.001) and surface changes (P < 0.001) were significantly associated with LNM. On multivariate analysis, tumor size (OR = 11.53, 95%CI: 2.51-52.93, P = 0.002) and atypical surface (OR = 27.44, 95%CI: 5.96-126.34, P < 0.001) changes were independent risk factors for LNM. The likelihood of atypical endoscopic features increased as tumor size increased. Atypical endoscopic features were associated with LNM in rectal NETs < 10 mm (P = 0.005) and 10-19 mm (P = 0.041) in diameter. Immunohistochemical staining showed that the rate of atypical endoscopic features was higher in non L-cell tumors. CONCLUSION Atypical endoscopic features as well as tumor size are predictive factors of LNM in patients with rectal NETs.

The significance of ectopic crypt formation in the differential diagnosis of colorectal polyps

BackgroundEctopic crypts, defined as abnormally positioned crypts that have lost their orientation toward the muscularis mucosae, have been suggested to be the best defining histologic feature of traditional serrated adenoma (TSA). However, the significance of ectopic crypt formation (ECF) in the distinction between TSA and conventional adenoma (CA) has rarely been studied.MethodsWe designed this study to determine if ECF can be found in CA and its presence is exclusive to TSA. We studied 107 TSAs and 191 CAs including 106 tubular adenomas (TAs), 66 tubulovillous adenomas (TVAs), and 19 villous adenomas (VAs).ResultsECF was identified in most (79.4%) but not all TSAs. Additionally, ECF was not infrequent in CA (62 of 191, 32.5%), and its presence correlated with the presence of a villous component and larger tumor size (each p <0.001).ConclusionsBased on its strong association with the presence of a villous component and larger tumor size, ECF appears to be involved in the protuberant growth of colorectal CA. Because ECF can be found in CA, particularly in cases with a villous component, the possibility of CA should be considered before making a diagnosis of TSA when encountering colorectal polyps with ECF.Virtual SlidesThe virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_212