The advent of the first electric driven EUS-guided 17 gauge core needle biopsy - A pilot study on subepithelial lesions

BACKGROUND AND AIMS

This pilot study aimed to evaluate safety and tissue sampling from subepithelial lesions (SEL) in the upper gastrointestinal tract with a novel electric motor driven endoscopic ultrasonography (EUS)-guided 17-gauge (G) size core needle biopsy (CNB) instrument.

METHODS

An investigator-led prospective open label, performance and safety control study, including seven patients (female n = 4, median 71 y, range 28-75) with a determined SEL (median size 30 mm, range 17-150 mm) in the upper digestive tract (stomach n = 6, duodenum n = 1) were eligible and later followed up 14 days after index procedure. All investigations were completed according to protocol with three FNB 22-G passes with four fanning strokes and two EndoDrill® 17-G passes with three fanning strokes.

RESULTS

Quality of samples as 'visible pieces' (>5 mm): FNB (n = 5/7) (fragmented/blood imbibed n = 1, poor tissue quantity n = 1) compared with 17-G CNB (n = 7/7). Histological result which led to final diagnosis (leiomyoma n = 2, adenocarcinoma n = 1, schwannoma n = 1, neuroendocrine tumour n = 1, desmoid tumour n = 1 and gastrointestinal stromal tumour (GIST) n = 1) could be obtained with the 17-G CNB instrument in all seven patients. FNB technique reached correct diagnosis in six patients. No serious adverse event were recorded.

CONCLUSIONS

By using an electric driven 17-G biopsy device, a true cylinder of core tissue can be obtained in one single puncture from the area of interest reducing the need for a second sampling. The absolute benefit of EUS-guided CNB is that the sample can be handled and histologically prepared in the same manner as standard percutaneous core needle sample, e.g., breast and prostate cancer.

Endoscopic ultrasound-based application system for predicting endoscopic resection-related outcomes and diagnosing subepithelial lesions: Multicenter prospective study

OBJECTIVES

Subepithelial lesions (SELs) are associated with various endoscopic resection (ER) outcomes and diagnostic challenges. We aimed to establish a tool for predicting ER-related outcomes and diagnosing SELs and to investigate the predictive value of endoscopic ultrasound (EUS).

METHODS

Phase 1 (system development) was performed in a retrospective cohort (n = 837) who underwent EUS before ER for SELs at eight hospitals. Prediction models for five key outcomes were developed using logistic regression. Models with satisfactory internal validation performance were included in a mobile application system, SEL endoscopic resection predictor (SELERP). In Phase 2, the models were externally validated in a prospective cohort of 200 patients.

RESULTS

An SELERP was developed using EUS characteristics, which included 10 models for five key outcomes: post-ER ulcer management, short procedure time, long hospital stay, high medication costs, and diagnosis of SELs. In Phase 1, 10 models were derived and validated (C-statistics, 0.67-0.99; calibration-in-the-large, -0.14-0.10; calibration slopes, 0.92-1.08). In Phase 2, the derived risk prediction models showed convincing discrimination (C-statistics, 0.64-0.73) and calibration (calibration-in-the-large, -0.02-0.05; calibration slopes, 1.01-1.09) in the prospective cohort. The sensitivities and specificities of the five diagnostic models were 68.3-95.7% and 64.1-83.3%, respectively.

CONCLUSION

We developed and prospectively validated an application system for the prediction of ER outcomes and diagnosis of SELs, which could aid clinical decision-making and facilitate patient-physician consultation. EUS features significantly contributed to the prediction.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, http://www.chictr.org.cn (ChiCTR2000040118).

Large Inflammatory Myofibroblastic Tumor of the Esophagus: A Case Report and Literature Review

Inflammatory myofibroblastic tumor (IMT) is a rare tumor composed of myofibroblasts with inflammatory blood cell infiltration. It commonly occurs in the lungs and rarely in the esophagus. We herein report a valuable case of IMT originating in the esophagus. A 60-year-old Japanese woman with dysphagia had a large subepithelial lesion in the cervical esophagus, which was 15 cm in length. Surgical resection was performed to confirm the pathological diagnosis and improve the symptoms. The postoperative diagnosis was IMT composed of multiple nodules. There was no recurrence or metastasis within one year after surgery.

Endoscopic Ultrasonography-Guided Fine-Needle Aspiration for Duodenal Subepithelial Lesions Showing a Hypoechoic Mass on Endoscopic Ultrasound Imaging

BACKGROUND/AIMS

For duodenal subepithelial lesions showing a hypoechoic mass on endoscopic ultrasound imaging, the utility of endoscopic ultrasound-guided fine-needle aspiration and the frequency of histological types have not been the focus of previous literature. This study aimed to clarify this.

MATERIALS AND METHODS

This prospective observational study enrolled 22 consecutive patients who underwent endoscopic ultrasoundguided fine-needle aspiration for duodenal subepithelial lesions with hypoechoic mass on endoscopic ultrasound. Immunohistochemical analysis was performed for all endoscopic ultrasound-guided fine-needle aspiration and surgically resected specimens. The main outcome measures were the technical results of endoscopic ultrasound-guided fine-needle aspiration and the frequency of histological types of duodenal subepithelial lesions with hypoechoic mass.

RESULTS

Thirteen fine-needle aspiration specimens were obtained from the duodenal bulb and eight from the descending duodenal region. The puncture was not performed because of intervening vessels in one patient. The diagnostic rate was 81% (95% confidence interval: 58.1-94.6, 17/21 patients). In 12 patients receiving surgical resection (excluding one cancellation of endoscopic ultrasoundguided fine-needle aspiration), the diagnostic accuracy of endoscopic ultrasound-guided fine-needle aspiration was 75% (95% confidence interval: 42.8-94.5, 9/12 patients). No complications were observed. The histopathological diagnoses included 11 cases of gastrointestinal stromal tumor (50%), 2 cases of leiomyoma (9%), 2 cases of metastatic cancer (9%), 2 cases of benign inconclusive, and 1 case each of carcinoid, malignant lymphoma, leiomyosarcoma, gauzeoma, and aberrant pancreas (4.5% each). The frequency of malignant tumors in the duodenal subepithelial lesions with hypoechoic mass group was 73% (16/22 patients).

CONCLUSIONS

Endoscopic ultrasound-guided fine-needle aspiration for duodenal subepithelial lesions with hypoechoic mass was safe and accurate. As duodenal subepithelial lesion with hypoechoic mass has a reasonably high possibility of containing malignant tumors, it is desirable to perform endoscopic ultrasound-guided fine-needle aspiration.

[Endoscopic ultrasound in the lower gastrointestinal tract]

Endoscopic ultrasound is a minimally invasive modality that combines endoscopy with ultrasound, providing a possibility to visualize the wall of the gastrointestinal tract and adjacent tissues and organs. Since the development of the modality in the 1980s, advancements in endoscopic ultrasound technology have led to increasingly broadening indications: besides diagnostic indications, therapeutic indications have also expanded greatly. According to recent guidelines regarding rectal cancer staging, rectal ultrasonography is mainly considered to be a secondary imaging modality compared to magnetic resonance imaging. With the use of forward-viewing echoendoscopes and ultrasound miniprobes that can be inserted through the working channel of the endoscope, endoscopic ultrasound technology can be expanded to proximal, colonic areas as well. Rectal ultrasonography can also play an important role in the differential diagnosis of subepithelial lesions, in the detection of rectal varices, in the diagnosis of inflammatory bowel diseases as well as perianal complications. Diagnostic accuracy can further be improved with the addition of ultrasound-guided sampling in certain cases. Currently, therapeutic indications are more like promising possibilities, than part of everyday clinical practice, but this might change in the near future. The purpose of this review is to summarize the current indications of rectal ultrasound in the clinical practice, including diagnostic and therapeutic ones as well. Orv Hetil. 2023; 164(30): 1176-1186.

A combined radiomic model distinguishing GISTs from leiomyomas and schwannomas in the stomach based on endoscopic ultrasonography images

BACKGROUND

Endoscopic ultrasonography (EUS) is recommended as the best tool for evaluating gastric subepithelial lesions (SELs); nonetheless, it has difficulty distinguishing gastrointestinal stromal tumors (GISTs) from leiomyomas and schwannomas. GISTs have malignant potential, whereas leiomyomas and schwannomas are considered benign.

PURPOSE

This study aimed to establish a combined radiomic model based on EUS images for distinguishing GISTs from leiomyomas and schwannomas in the stomach.

METHODS

EUS images of pathologically confirmed GISTs, leiomyomas, and schwannomas were collected from five centers. Gastric SELs were divided into training and testing datasets based on random split-sample method (7:3). Radiomic features were extracted from the tumor and muscularis propria regions. Principal component analysis, least absolute shrinkage, and selection operator were used for feature selection. Support vector machine was used to construct radiomic models. Two radiomic models were built: the conventional radiomic model included tumor features alone, whereas the combined radiomic model incorporated features from the tumor and muscularis propria regions.

RESULTS

A total of 3933 EUS images from 485 cases were included. For the differential diagnosis of GISTs from leiomyomas and schwannomas, the accuracy, sensitivity, specificity, and area under the receiver operating characteristic curve were 74.5%, 72.2%, 78.7%, and 0.754, respectively, for the EUS experts; 76.8%, 74.4%, 81.0%, and 0.830, respectively, for the conventional radiomic model; and 90.9%, 91.0%, 90.6%, and 0.953, respectively, for the combined radiomic model. For gastric SELs <20 mm, the accuracy, sensitivity, specificity, and area under the receiver operating characteristic curve of the combined radiomic model were 91.4%, 91.6%, 91.1%, and 0.960, respectively.

CONCLUSIONS

We developed and validated a combined radiomic model to distinguish gastric GISTs from leiomyomas and schwannomas. The combined radiomic model showed better diagnostic performance than the conventional radiomic model and could assist EUS experts in non-invasively diagnosing gastric SELs, particularly gastric SELs <20 mm.

Magnifying Endoscopy with Narrow-Band Imaging for Duodenal Neuroendocrine Tumors

Duodenal neuroendocrine tumors (NETs) are rare subepithelial tumors that arise from the neuroendocrine cells beneath the epithelial layer. However, an accurate histopathological diagnosis is difficult when tissue samples are obtained using conventional endoscopic forceps biopsy alone. This study aimed to evaluate the magnifying endoscopy with narrow-band imaging (ME-NBI) findings of duodenal NETs. We retrospectively analyzed a database of 22 duodenal NETs from 21 patients who underwent ME-NBI between January 2011 and June 2022. The ME-NBI, endosonographic, and histopathologic findings of duodenal NETs were analyzed. Nineteen lesions were located in the bulb, two were located in the superior duodenal angle, and one was located in the second portion of the duodenum. Eighteen lesions (82%) had IIa morphology, and nine (41%) had central depression on the surface. On endoscopic ultrasonography, almost all lesions (20/22, 91%) were located in the second and/or third layers, and the median tumor size was 6 mm. During ME-NBI, the microsurface pattern was regular in 18 lesions (82%) and absent in 4 (18%). The microvascular pattern was regular in 17 lesions (77%), irregular in 4 (18%), and absent in 1 (5%). Thickened subepithelial vessels were observed in 15 (68%) lesions. There was no difference in tumor size according to the presence or absence of thickened subepithelial vessels (6.1 ± 1.8 mm vs. 5.9 ± 3.8 mm, p = 0.860). In conclusion, the characteristic ME-NBI findings of duodenal NETs were regular microsurface and microvascular patterns and the presence of thickened subepithelial vessels. These ME-NBI features may be useful for differentiating duodenal NETs from other duodenal subepithelial lesions.

Duodenal Heterotopic Pancreas with a Large Retention Cyst: A Case Report and Literature Review

A 75-year-old man was referred to our hospital with a suspected pancreatic cyst. Imaging tests revealed a 3-cm cystic lesion located ventrally in the duodenal bulbus, which was suspected to be a duplication cyst with its muscularis propria contiguous to that of the duodenum. One year later, the cyst grew to 6 cm due to intracystic hemorrhaging; therefore, surgery was performed. Histopathology revealed a heterotopic pancreas (HP) in the duodenal wall. The diagnosis was a large, non-malignant retention cyst. Inflammation due to impaired outflow of pancreatic juice from the HP was identified as the cause of cyst enlargement.

Natural Course of Asymptomatic Upper Gastrointestinal Subepithelial Lesion of 2 cm or Less in Size

There is limited evidence of a natural course of an upper gastrointestinal (UGI)-subepithelial lesion (SEL) of 2 cm or less in size. This study aims to determine the natural course of UGI-SELs and find the risk factors of the endoscopic and endoscopic ultrasonography (EUS) findings associated with an increase in size. The medical records of 2539 patients with UGI-SELs between 2004 and 2016 were reviewed retrospectively. A total of 672 SELs of 2 cm or less in size were analyzed through EUS and followed up for at least 36 months. The mean follow-up duration was 68 months (range: 36-190 months), and 97 SELs (14.4%) showed an increase in size with a mean increase rate of 1.2 mm/year. Initial size (aOR 1.03, 95% confidence interval (CI) 1.01-1.06), an endoscopic finding of a hemorrhagic spot (aOR 3.13, 95% CI 1.14-8.60), and an EUS finding of a lesion in the fourth layer (aOR 1.87, 95% CI (1.21-2.88) were related to an increase in size. An endoscopic finding of translucidity (aOR 0.28, 95% CI (0.10-0.76) and an EUS finding of calcification (aOR 0.30, 95% CI 0.09-0.95) were inversely related to an increase in size. There was no death related to UGI-SELs during the follow-up. While most UGI-SELs of 2 cm or less in size showed no significant size change and favorable prognosis, an individualized follow-up strategy needs to be considered in case of the presence of hemorrhagic spots and lesions in the fourth layer.

Endoscopic Ultrasonography-guided Fine-needle Aspiration Cytology Combined with a Cell-block Method for Gastrointestinal Subepithelial Lesions

Objective The diagnostic accuracy of an endoscopic ultrasound-guided fine-needle aspiration cytology/biopsy combined with a cell-block method (FNA-CB) for gastrointestinal subepithelial lesions (GI-SELs) has not been fully studied. Methods A total of 109 patients (with 110 GI-SELs) were evaluated to clarify the rate of obtaining evaluable histology specimens using FNA-CB. In addition, we investigated the following: 1) the accuracy for determining the histology, 2) effects of the number of cell clusters obtained via FNA-CB, 3) correlation of the Ki67 labelling index (Ki67LI) of the gastrointestinal stromal tumor (GIST) lesions between FNA-CB and resected specimens, and 4) clinical courses for patients followed up after FNA-CB. Results Of the 110 GI-SELs for which FNA-CB was performed, 95 (86%) were able to be histologically evaluated using the first FNA-CB. For the 70 resected GI-SELs, the accuracy of FNA-CB to determine histology was 96%, remaining at 90% even when only a few cell clusters were obtained. The concordance rate of the risk-grouping of GIST (high-risk, Ki67LI ≥8; low-risk, <8) between FNA-CB and resected specimens was 84%. Of the 29 patients followed up after the first FNA-CB, 12 with benign GI-SELs determined using the first FNA-CB showed no obvious increases in their GI-SEL sizes. Conclusion Since FNA-CB can be used to determine the histology and reproductive activity of GI-SELs accurately, not only preoperative histological confirmation but also reliable information to determine clinical plans, such as follow-up without surgery or neoadjuvant chemotherapy, can be obtained.

The Diagnosis of Small Gastrointestinal Subepithelial Lesions by Endoscopic Ultrasound-Guided Fine Needle Aspiration and Biopsy

Endoscopic ultrasonography (EUS) has been widely accepted in the diagnosis of all types of tumors, especially pancreatic tumors, lymph nodes, and subepithelial lesions (SELs). One reason is that the examination can provide a detailed observation, with tissue samples being immediately obtained by endoscopic ultrasound-guided fine needle aspiration (EUS-FNA). Many SELs are detected incidentally during endoscopic examinations without symptoms. Most SELs are mesenchymal tumors originating from the fourth layer, such as gastrointestinal stromal tumors (GISTs), leiomyomas, and schwannomas. GISTs are potentially malignant. Surgical treatment is recommended for localized GISTs of ≥20 mm. However, the indications for the diagnosis and follow-up of GISTs of <20 mm in size are controversial. There are several reports on the rapid progression or metastasis of small GISTs. Therefore, it is important to determine whether a SEL is a GIST or not. The main diagnostic method is EUS-FNA. Recently, endoscopic ultrasound-guided fine needle biopsy (EUS-FNB) using a new biopsy needle has been reported to obtain larger tissue samples. Additionally, various biopsy methods have been reported to have a high diagnostic rate for small GISTs. In local gastric SELs, regardless of the tumor size, EUS can be performed first; then, EUS-FNA/B or various biopsy methods can be used to obtain tissue samples for decision-making in relation to therapy and the follow-up period.

Usefulness of a Fork-Tip Needle in Endoscopic Ultrasound-Guided Fine-Needle Biopsy for Gastric Subepithelial Lesions

The sample adequacy and diagnostic accuracy of an endoscopic ultrasound (EUS)-guided fine-needle aspiration (EUS-FNA) for gastric subepithelial lesions (SELs) have been reported to be imperfect. To resolve these issues, a fork-tip needle as an EUS-guided fine-needle biopsy (FNB) needle has been developed. This study was conducted to evaluate the usefulness of a fork-tip needle in an EUS-FNB for gastric SELs. Seventy-nine patients who received an EUS-FNA or FNB using a fork-tip needle for gastric SELs were included in the study. The sample adequacy and diagnostic accuracy were compared between the EUS-FNB with the fork-tip needle group (fork-tip group, n = 13) and the EUS-FNA with FNA needle group (FNA group, n = 66). In addition, a multivariate analysis of the factors influencing diagnostic accuracy was conducted. Regarding sample adequacy, there was no significant difference between the groups (100% vs. 90.9%, respectively; p = 0.582). The diagnostic accuracy of the fork-tip group was numerically higher than that of the FNA group (92.3% vs. 81.8%, respectively; p = 0.682). In a multivariate analysis, the diagnostic accuracy was related to the tumor size and location of the SEL but not to the needle type. In conclusion, this study does not show statistical superiority, but suggests the useful potential of a fork-tip needle.

Recent Advances in Endosonography-Elastography: Literature Review

Ultrasonographic elastography is a modality used to visualize the elastic properties of tissues. Technological advances in ultrasound equipment have supported the evaluation of elastography (EG) in endosonography (EUS). Currently, the usefulness of not only EUS-strain elastography (EUS-SE) but also EUS-shear wave elastography (EUS-SWE) has been reported. We reviewed the literature on the usefulness of EUS-EG for various diseases such as chronic pancreatitis, pancreatic solid lesion, autoimmune pancreatitis, lymph node, and gastrointestinal and subepithelial lesions. The importance of this new diagnostic parameter, "tissue elasticity" in clinical practice might be applied not only to the diagnosis of liver fibrosis but also to the elucidation of the pathogeneses of various gastrointestinal diseases, including pancreatic diseases, and to the evaluation of therapeutic effects. The most important feature of EUS-EG is that it is a non-invasive modality. This is an advantage not found in EUS-guided fine needle aspiration (EUS-FNA), which has made remarkable progress in the field of diagnostics in recent years. Further development of artificial intelligence (AI) is expected to improve the diagnostic performance of EUS-EG. Future research on EUS-EG is anticipated.

Two Cases of Endometriosis in the Cecum Detected by Contrast-enhanced Computed Tomography with Air/Carbon Dioxide Insufflation

We herein report two patients with endometriosis in the cecum. Both patients presented with a protruding, subepithelial tumor on colonoscopy and were diagnosed with cecal endometriosis after surgical resection. It is notable that the cecal lesions were not initially identified on computed tomography (CT), while CT colonography with air/carbon dioxide insufflation resulted in the detection of the cecal tumor. These cases highlight the possibility of false-negative results on conventional CT in patients with cecal endometriosis. We consider CT colonography with air/carbon dioxide insufflation useful for detecting cecal tumors in such cases.

Outcomes of endoscopic ultrasound and endoscopic resection of gastrointestinal subepithelial lesions: a single-center retrospective cohort study

Background

Endoscopic resection (ER) is an emerging therapeutic alternative for subepithelial gastrointestinal lesions (SELs). We aimed to determine whether size, layer of origin, and histology based on endoscopic ultrasound (EUS) and EUS-guided sampling (EUS-GS) influenced the outcomes and selection of patients for ER.

Methods

We performed a retrospective review of patients who underwent EUS, EUS-GS and resection of SELs from 2012-2019. Two pathologists reviewed the histology and layer of origin of all resected specimens, serving as the criterion for EUS accuracy.

Results

Seventy-three patients were included, of whom 59 (81%) were gastric SELs. Per EUS, median lesion size was 21 mm (interquartile range 15-32), and 63 (86%) originated from the 4th layer. The overall accuracy of EUS and EUS-GS in predicting the layer of origin and histology was 88% (95% confidence interval [CI] 77-94%) and 96% (95%CI 87-98%), respectively. Based on EUS, 18 (25%) patients were referred for ER, 5 (7%) to laparoscopic-endoscopic cooperative surgery, and 50 (68%) to surgery. Size >20 mm was associated with the type of resection approach (P=0.005), while layer of origin and histology were not (P=0.06 and P=0.09, respectively). When SELs were inaccurately classified (n=4) there were no adverse events or revision of the resection approach.

Conclusions

EUS plays an important role in the outcome of resection approach for SELs, with size significantly influencing the selection for ER. In patients undergoing ER, no revised resections were needed when EUS was inaccurate.

Interobserver Reliability of Endoscopic Ultrasonography: Literature Review

Endoscopic ultrasonography (EUS) has been applied to the diagnosis of various digestive disorders. Although it has been widely accepted and its diagnostic value is high, the dependence of EUS diagnosis on image interpretation done by the endosonographer has persisted as an important difficulty. Consequently, high interobserver reliability (IOR) in EUS diagnosis is important to demonstrate the reliability of EUS diagnosis. We reviewed the literature on the IOR of EUS diagnosis for various diseases such as chronic pancreatitis, pancreatic solid/cystic mass, lymphadenopathy, and gastrointestinal and subepithelial lesions. The IOR of EUS diagnosis differs depending on the disease; moreover, EUS findings with high IOR and those with IOR that was not necessarily high were used as diagnostic criteria. Therefore, to further increase the value of EUS diagnosis, EUS diagnostic criteria with high diagnostic characteristics based on EUS findings with high IOR must be established.

EUS-guided tissue sampling with a 20-gauge core biopsy needle for the characterization of gastrointestinal subepithelial lesions: A multicenter study

Background and Objective:

A new 20-gauge (G) biopsy needle with a core-trap technology has been developed with a large core size and enhanced flexibility. The aim of this multicenter study was to determine the feasibility, efficacy, and safety of EUS-guided fine-needle biopsy (EUS-FNB) with the new 20G needle in diagnosing subepithelial lesions (SELs).

Materials and Methods:

Retrospectively collected data from consecutive patients with SELs undergoing EUS-FNB with the 20G needle at five centers were analyzed.

Results:

A total of 50 SELs were included. The mean lesion size was 43.1 ± 17.5 mm. The lesion locations were esophagus (n = 1), stomach (n = 37), distal duodenum (n = 5), rectum (n = 6), and colon (n = 1). The procedure was technically feasible in all patients. Definitive diagnosis with full histological assessment including immunohistochemistry was obtained in 88% (44/50) of the patients. Considering malignant versus benign lesions, the sensitivity, specificity, positive predictive value, and negative predictive value were 85% (95% confidence interval [CI] 70.2–94.3), 100% (95% CI 58.7%–100%), 100% (95% CI 85.1%–100%), and 62.5 (95% CI 27.7–84.8), respectively. No major complications requiring additional care have been observed.

Conclusions:

In this multicenter study, we found that EUS-FNB with the new 20G core needle is an effective and safe method for the diagnosis of SELs with a high rate of producing adequate histological material and high diagnostic accuracy even from difficult-to-approach anatomical locations.

Diagnostic ability of a 22G Franseen needle in endoscopic ultrasound-guided fine needle aspiration of subepithelial lesions

The differential diagnosis of gastrointestinal subepithelial lesions (SELs) such as gastrointestinal stromal tumors from other benign tumors is important. In the present study, adequate sample rates of endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) with a 22G Franseen needle for SELs were evaluated. The present study included 57 consecutive lesions (61 sessions) of EUS-FNA using a 22G needle to evaluate SELs between July 2013 and October 2017. Adequate sample rates were compared retrospectively between a 22G conventional needle group (C group) and a 22G Franseen needle group (F group). The overall adequate sample rate was 80.3%. The adequate sample rates in the C and F groups were 75.0% (33/44) and 94.1% (16/17), respectively (P=0.15). For lesions ≥20 mm, the adequate sample rates were 82.8% (24/29) in the C group and 91.7% (11/12) in the F group, 8.9% higher in the F group. However, for lesions <20 mm, the adequate sample rates were 60% (9/15) in the C group and 100% (5/5) in the F group, 40% higher in the F group (P=0.65, 0.26). In conclusion, the results of the present study suggested that using a 22G Franseen needle for EUS-FNA evaluation of SELs may improve adequate sample rates in small lesions <20 mm in diameter.

Heterotopic Respiratory Mucosa in the Rectum: An Unusual Type and Site of Heterotopia in the Gastrointestinal Tract

Although pancreatic and gastric heterotopias are common findings in the gastrointestinal tract, heterotopic respiratory mucosa (HRM) in the rectum is extremely rare and has only been reported twice previously. We are presenting, to our knowledge, the third case of HRM in the rectum. A 56-year-old man with a history of chronic diarrhea presented for diagnostic colonoscopy, where he was found to have a rectal subepithelial nodule. He was subsequently referred to a tertiary medical center for further evaluation with rectal endoscopic ultrasound. Endoscopically, the nodule was hypoechoic, 2 to 3 mm in size, located in the submucosa, and did not appear to invade the muscularis propria. An uncomplicated endoscopic submucosal resection was subsequently performed. Microscopically, the nodule showed a multicystic complex lesion located in the submucosa, lined by ciliated pseudostratified columnar epithelium and surrounded by thin to moderately thick smooth muscle bundles and multiple lobules of seromucinous glands. There was associated acute and chronic inflammation. The rectum overlying the subepithelial lesion was lined by congested and edematous colonic mucosa and demonstrated no connection with the underlying cystic lesion. Immunohistochemical stains showed positive p63 basal cell staining in the respiratory epithelium of the lesion, while CDX2, TTF-1, and estrogen receptors were all negative. HRM is a benign nonneoplastic lesion with unclear etiology. Pathologists and gastroenterologists should be aware of this entity and consider it in their differential diagnosis for a subepithelial nodule in the rectum, keeping in mind that neoplastic processes can also develop in this location.

A case of gastric lipoma resected by endoscopic submucosa dissection with difficulty in preoperative diagnosis

A 66-year-old man was referred to our hospital with an increasing subepithelial lesion in the gastric antrum. Using esophagogastroduodenoscopy, a tumor with a steep, 20-mm-high rise protruding in the lumen was observed. The mucosal surface of the tumor was reddish, with ulcers forming at the base. Moreover, the tumor was mobile and soft. A biopsy specimen was taken from the ulcer, but tumor tissue was not collected from the submucosa. Endoscopic ultrasonography (EUS) showed a high echoic mass in the submucosa. However, because the mucosal surface of the ulceration was red, the mesenchymal tumor with internal bleeding was inferred to be lipoma. Additionally, because the tumor was small, flexible, and soft, collecting tumor tissue under EUS-guided fine-needle aspiration was inferred as difficult. We were unable to make a final diagnosis because the lesion showed a small tumor with atypical macroscopic morphology. Therefore, endoscopic submucosa dissection (ESD) was chosen for the diagnostic treatment. Sodium hyaluronate sufficient for separation from the muscular layer was injected into the submucosa. Then submucosal dissection was performed just above the muscle layer. Results demonstrate the possibility of removing the tumor reliably without perforation. Pathological evaluation of the ESD specimen indicated a diagnosis of gastric lipoma.

Efficacy of endoscopic ultrasound-guided fine-needle aspiration for schwannoma: six cases of a retrospective study

BACKGROUND

Schwannomas are difficult to diagnose using imaging alone. Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is an effective and safe tissue sampling technique. Nevertheless, few reports have described EUS-FNA for schwannoma.

OBJECTIVE

This study evaluates the efficacy of EUS-FNA for diagnosing schwannoma.

METHODS

This retrospective study examined six consecutive schwannoma patients who were diagnosed as having schwannoma either from EUS-FNA results or from surgically resected specimens. The primary endpoint was diagnostic accuracy of EUS-FNA for schwannoma. The secondary endpoint was EUS-FNA safety.

RESULTS

Based on cytomorphologic features and immunocytochemistry results after EUS-FNA, 4 out of 6 patients (66.7%) were diagnosed with schwannoma. The diagnoses before EUS-FNA were the following: 3 cases of gastric subepithelial lesion (SEL, suspicious for gastrointestinal stromal tumor), 1 case of intraperitoneal tumor, 1 case of retroperitoneal tumor, and 1 case of pancreatic tumor, with sizes of 15-44 mm (median 36 mm). No case was diagnosed as schwannoma solely based on image findings. Two cases of gastric SELs could not be diagnosed as schwannoma by EUS-FNA before surgery. Inadequate sampling and a lack of additional material for immunohistochemical studies could have engendered less-definite diagnoses in those cases. No procedural adverse events occurred.

CONCLUSION

The diagnostic accuracy rate of EUS-FNA for schwannoma is somewhat low. However, tissue samples were obtained safely using this method. Moreover, it is an important procedure for diagnosing schwannoma, which cannot be diagnosed solely from image findings.

Endoscopic ultrasonography diagnosis of subepithelial lesions

Using endoscopic ultrasonography (EUS), it is practicable to diagnose subepithelial lesions (SEL) with originating layer, echo level, and internal echo pattern etc. Lipoma, lymphangioma, and cyst have characteristic features; therefore, there is no need for endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA). Ectopic pancreas and glomus tumors, which originate from the third and fourth layers, are frequently seen in the antrum. However, ectopic pancreas located in the fundus or body is large and originates from the third and fourth layers (thickening of fourth layer). Each subepithelial lesion has characteristic findings. However, imaging differentiation of tumors originating from the fourth layer is very difficult, even if contrast echo is used. Therefore, EUS-FNA should be done in these tumors, but the diagnostic yield for small lesions is not sufficient for clinical demands. Generally, those tumors, including small ones, should be first followed up in 6 months, then yearly follow up in cases of no significant change in size and features. When those tumors become larger than 1-2 cm, EUS-FNA is recommended. Furthermore, unusual SEL and SEL with malignant findings such as nodular, heterogeneous, anechoic area, and ulceration indicate EUS-FNA. Cap-attached forward-viewing echoendoscope is very helpful for EUS-FNA of small SEL.

Surgical Outcomes of Laparoscopic Resection for Subepithelial Lesions on the Gastric Fundus Performed in the Supine or Lateral Decubitus Position

BACKGROUND

Laparoscopic resection of gastric subepithelial lesions (SELs) located on the posterior wall of the gastric fundus is technically difficult and time-consuming. To facilitate access, we propose performing the laparoscopic procedure with patients in a right lateral decubitus position, rather than the standard supine position. The aim of our study was to compare operative and clinical outcomes for laparoscopic SEL resection performed in either the right lateral decubitus or the traditional supine position.

METHODS

The analysis was based on the data of 62 patients who underwent laparoscopic resection of SELs of the gastric fundus at Chonnam National University Hospital: 30 patients in the supine position (SUP) group and 32 in the right lateral decubitus position (RLD) group. All surgeries were performed by a single surgeon. Between-group comparisons were evaluated by Student's t, chi-squared, or Fisher's least squared tests, as appropriate for the data set.

RESULTS

Compared with the SUP group, the RLD had shorter operative time (103 minutes versus 52 minutes, P < .001), less intraoperative blood loss (71 mL versus 31 mL, P < .001), and lower C-reactive protein levels on postoperative days 1 and 2 (P < .005). Time to first flatus and length of hospital stay were comparable between groups.

CONCLUSION

Laparoscopic gastric wedge resection for SELs on the gastric fundus in the right lateral decubitus position is feasible and safe, and provides operative advantages over the supine position.

Endoscopic submucosal dissection for rectal carcinoid tumour using the Clutch Cutter

BACKGROUND

To reduce the risk of complications related to endoscopic submucosal dissection (ESD) using knives, we developed the Clutch Cutter (CC), which can grasp and incise the target tissue similarly to biopsy techniques using an electrosurgical current. The aim of this study was to evaluate the efficacy and safety of ESD using the CC for removal of rectal carcinoid tumours.

METHODS

Between December 2009 and December 2011, we prospectively enrolled seven patients (seven lesions) on 7 different days. Patients were endoscopically diagnosed with rectal subepithelial lesions (upper rectum, n = 3; lower rectum, n = 4) within the level 3 layer and without lymph node involvement, with the diagnosis confirmed by preliminary endoscopy, endoscopic ultrasound and endoscopic biopsies. ESD using the CC was performed in all cases, and the therapeutic efficacy, safety and tumour recurrence were assessed.

RESULTS

All lesions were treated easily and safely, and there were no inadvertent incisions. En bloc resection was obtained in all cases, and histologic tumour-free lateral/basal margins were obtained in six of the seven patients. No delayed haemorrhage, perforation or tumour recurrence occurred.

CONCLUSION

ESD using the CC appears to be an easy, safe and technically efficient method for resecting rectal carcinoid tumour.

Ligation-assisted endoscopic enucleation for treatment of esophageal subepithelial lesions originating from the muscularis propria: a preliminary study

An innovative ligation-assisted endoscopic enucleation (EE-L) technique was developed for the diagnosis and treatment of esophageal subepithelial lesions (smaller than 12 mm) originating from muscularis propria by combining endoscopic band ligation and endoscopic enucleation techniques. The aim of the study was to evaluate efficacy and safety of EE-L technique in the treatment of esophageal subepithelial lesions (smaller than 12 mm) originating from muscularis propria. Forty-seven esophageal subepithelial lesions (smaller than 12 mm) originating from the muscularis propria in 44 patients were treated with EE-L between September 2010 and September 2012. The lesion was first aspirated into the transparent cap attached to the tip of endoscope. The elastic band was then released around its base. The purpose of ligation was to force the lesion to assume a polypoid form with a pseudostalk. Endoscopic enucleation was then performed until the tumor was completely enucleated from muscularis propria using a hook knife and forceps. All tumors (median diameter: 8.2 ± 2.3 mm, range: 4-12 mm) were enucleated completely. Histopathology identified 45 tumors (95.7%) as leiomyoma, 2 (4.3%) tumors as gastrointestinal stromal tumor with very low risk. The mean time of the EE-L procedure was 12.5 ± 4.6 minutes (range: 6-23 minutes). Two patients experienced self-limiting, non-life-threatening hemorrhage after EE-L. No perforation and massive hemorrhage requiring further endoscopic or surgical intervention occurred. There were no recurrences during the 6-24 months follow-up period. EE-L offers the option of localized treatment of small esophageal muscularis propria tumors (smaller than 12 mm) with relatively few complications and low mortality, and provides the advantage of allowing a histopathological diagnosis. All the resected lesions in this study had a benign pathology.