Diagnostic findings of ultrasound-guided fine-needle aspiration cytology for gastrointestinal stromal tumors: proposal of a combined cytology with newly defined features and histology diagnosis

Ki-67 index assessment on FNA specimens of gastrointestinal stromal tumor: Correlation with mitotic rate and potential predictive value for risk stratification

BACKGROUND

Risk assessment of gastrointestinal stromal tumor (GIST) is challenging on cytology specimens. This study aims to determine whether Ki-67 index evaluated on fine-needle aspiration (FNA) specimens can correlate with the mitotic rate of GIST in surgical specimens and provide further risk assessment.

METHODS

Cases with cell blocks containing adequate tumor cells and surgical resections were included. Ki-67 immunostain was retrospectively performed on cell block sections, and Ki-67 index was calculated on the "hot spot" areas.

RESULTS

This study included 50 GIST cases from stomach (n = 45; 90%), duodenum (n = 4; 8%), and distal esophagus (n = 1; 2%). The tumor size ranged from 1.5 cm to 21 cm (mean, 5.4 cm). Based on the mitotic count, 37 GISTs (74%) had low mitotic rate (LMR) and 13 GISTs (26%) had high mitotic rate (HMR). The spindle cell, epithelioid, and mixed types accounted for 60%, 14%, and 26% of GIST, respectively. Ki-67 index counted on cell block sections correlated well with mitotic count evaluated in surgical specimens (r = 0.8031). Mean Ki-67 index was higher in HMR than LMR groups (3.5% vs. 1%, p < .001). The receiver operating characteristic curve using Ki-67 index to predict mitotic rate was further analyzed, and area under the curve was 0.839. Using a cutoff of 2.5% yielded a sensitivity of 70% at 92% specificity.

CONCLUSIONS

This study demonstrates good correlations between Ki-67 index and mitotic count or risk stratification, suggesting that Ki-67 index evaluated on cytology specimens may offer a promising approach to preoperatively predict the mitotic rate and risk of GIST.

Comparison of diagnostic performances of slow-pull suction and standard suction in endoscopic ultrasound-guided fine needle biopsy for gastrointestinal subepithelial tumors

Background/Aims

Endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) is integral to the diagnosis of gastrointestinal (GI) subepithelial tumors (SETs). The impact of different EUS-FNB tissue sampling techniques on specimen adequacy and diagnostic accuracy in SETs has not been fully evaluated. This study aimed to compare the diagnostic outcomes of slow-pull (SP) and standard suction (SS) in patients with GI SETs.

Methods

In this retrospective comparative study, 54 patients were enrolled. Medical records were reviewed for location and size of the target lesion, FNB needle type/size, technical order, specimen adequacy, diagnostic yield, and adverse events. The acquisition rate of adequate specimens and diagnostic accuracy were compared according to EUS-FNB techniques.

Results

The mean lesion size was 42.6±36.4 mm, and most patients were diagnosed with GI stromal tumor (75.9%). The overall diagnostic accuracies of the SP and SS techniques were 83.3% and 81.5%, respectively (p=0.800). The rates of obtaining adequate core tissue were 79.6% and 75.9%, respectively (p=0.799). No significant clinical factors affected the rate of obtaining adequate core tissue, including lesion location and size, FNB needle size, and final diagnosis.

Conclusions

SP and SS had comparable diagnostic accuracies and adequate core tissue acquisition for GI SETs via EUS-FNB.

Advancements in the Diagnosis of Gastric Subepithelial Tumors

A diagnosis of subepithelial tumors (SETs) is sometimes difficult due to the existence of overlying mucosa on the lesions, which hampers optical diagnosis by conventional endoscopy and tissue sampling with standard biopsy forceps. Imaging modalities, by using computed tomography and endoscopic ultrasonography (EUS) are mandatory to noninvasively collect the target's information and to opt candidates for further evaluation. Particularly, EUS is an indispensable diagnostic modality for assessing the lesions precisely and evaluating the possibility of malignancy. The diagnostic ability of EUS appears increased by the combined use of contrast-enhancement or elastography. Histology is the gold standard for obtaining the final diagnosis. Tissue sampling requires special techniques to break the mucosal barrier. Although EUS-guided fine-needle aspiration (EUS-FNA) is commonly applied, mucosal cutting biopsy and mucosal incision-assisted biopsy are comparable methods to definitively obtain tissues from the exposed surface of lesions and seem more useful than EUS-FNA for small SETs. Recent advancements in artificial intelligence (AI) have a potential to drastically change the diagnostic strategy for SETs. Development and establishment of noninvasive methods including AI-assisted diagnosis are expected to provide an alternative to invasive, histological diagnosis.

Reasons for Diagnostic Failure in Forty-Five Consecutive Mucosal Cutting Biopsy Examinations of Gastric Subepithelial Tumors

BACKGROUND/AIMS

Mucosal cutting biopsy (MCB) is useful for the histopathological diagnosis of gastric subepithelial tumors (SETs). However, there is little information on cases in which MCB did not establish a diagnosis. In the current study, we aimed to investigate the characteristics of cases in which MCB was unsuccessful.

METHODS

Cases in which MCB was used to histopathologically diagnose gastric SETs at Kobe University Hospital between August 2012 and October 2018 were retrospectively reviewed.

RESULTS

Forty-five cases in which MCB was used to diagnose 43 gastric SETs in 43 patients were analyzed. The median tumor size was 20 mm (range, 8-50 mm). Pathological examinations resulted in definitive and suspected diagnoses and no diagnosis in 29 (gastrointestinal stromal tumor: n=17, leiomyoma: n=7, aberrant pancreas: n=3, others: n=2), 6, and 10 cases, respectively. Failure to expose the tumor according to retrospective examinations of endoscopic images was significantly associated with no diagnosis. Other possible explanations included a less elevated tumor, biopsy of the surrounding field instead of the tumor due to the mobility, and poor endoscope maneuverability due to the tumor being close to the cardia.

CONCLUSION

Clear exposure of gastric SETs during MCB may improve the diagnostic rate of such examinations.

Impact of endoscopic ultrasound-guided fine-needle biopsy on the diagnosis of subepithelial tumors: A propensity score-matching analysis

BACKGROUND AND AIM

Immunohistological evaluations are essential for diagnosing subepithelial tumors (SET). However, endoscopic ultrasound-guided sampling using fine-needle aspiration (FNA) needles is limited in its ability to procure core tissue for immunostaining. Fine-needle biopsy (FNB) needles may mitigate this limitation. The present study aimed to examine the efficacy of FNB needles for procuring samples that enable the diagnosis of SET.

METHODS

One hundred sixty patients were included in the study and separated into those whose samples were obtained using FNB needles (FNB group) and those whose samples were procured using FNA needles (FNA group). Groups were compared regarding the conclusive diagnosis rate and unwarranted resection rate. Propensity score matching was introduced to reduce selection bias.

RESULTS

Rates at which conclusive diagnoses were reached through adequate immunohistological evaluations were 82% and 60% in the FNB and FNA groups, respectively; this difference was significant (P = 0.013). Unwarranted resection rate was significantly lower in the FNB group (2%) than in the FNA group (14%; P = 0.032). Multivariate analyses showed that lesions ≤20 mm were a significant risk factor for lower conclusive diagnosis rates following the use of FNB needles (P = 0.017).

CONCLUSIONS

Fine-needle biopsy needles can be useful for obtaining samples that facilitate the diagnosis of SET and for avoiding unwarranted resections. However, FNB needles may be less advantageous for small SET.

Cytological Findings of Gastrointestinal Stromal Tumor-Derived Bone Metastasis

OBJECTIVE

Procedures for diagnosing bone tumors should be rapid and minimally invasive. Thus, cytological examinations are more useful for such purposes than histological examinations. In order to identify cytomorphological findings that could be used to diagnose bone metastasis from gastrointestinal stromal tumors (GIST), previous cases were reviewed.

STUDY DESIGN

Cytological samples of 7 lesions from 4 patients with GIST-derived bone metastasis, which were obtained from 2001 to 2017 at the JFCR Cancer Institute Hospital, were reviewed.

RESULTS

The metastasis of GIST to the bone was clinically suspected before the cytological and histological examinations in all cases since they all involved other metastatic lesion(s), and characteristic osteolytic lesions were detected on radiological images. Although various cell shapes were encountered, spindle cell proliferation was seen in all cytological samples. No pleomorphism was apparent. Characteristic nuclear findings were observed. All of the cases could be diagnosed as GIST-derived bone metastasis.

CONCLUSION

GIST-derived bone metastasis can be diagnosed by examining cytological samples.

EUS-FNA WITH 19 OR 22 GAUGES NEEDLES FOR GASTRIC SUBEPITHELIAL LESIONS OF THE MUSCLE LAYER

Background:

Tissue diagnosis is required for gastric subepithelial lesions for differential diagnosis of GISTs. However, there has not been consensus about the best needle for EUS-guided sampling of these lesions.

Aim:

To evaluate the diagnostic yield of EUS-FNA for gastric subepithelial lesions of the proper muscle layer with large-bore 19 gauge needles.

Methods:

A prospectively maintained database was retrospectively reviewed to identify consecutive patients who underwent EUS-FNA with 19 and 22 gauge needles for gastric subepithelial lesions of the fourth endosonographic layer in a tertiary care referral center. EUS-FNA was performed by the same endosonographer, using the fanning technique, without on-site cytopathologist. Specimens were analysed through cell blocks by the same pathologist. Procedure results were categorized into diagnostic, defined as enough material for histopathology and immunohistochemistry, or nondiagnostic.

Results:

Eighty-nine patients (mean age: 59 years, 77% women) underwent 92 EUS-FNA with 19 (75) or 22 (17) gauge needles. Mean lesion size was 22.6 mm. Overall diagnostic yield was 88%. The diagnostic yield of 19 gauge was higher than that of 22 gauge needle (92%x70.6%; p=0.0410), and similar for lesions >2 cm and <2 cm (93.7%x90.7%; p=0.9563). The best performance for 19 gauge needles was obtained performing <3 needle passes. Complication rate was 2.8%.

Conclusions:

Diagnostic yield of EUS-FNA with 19 gauge needles is 92% for gastric subepithelial lesions of the proper muscle layer. It is safe and highly valuable for differentiation between GIST and leiomyoma, no matter the size of the lesion.

Surgical treatment of gastrointestinal stromal tumors of the stomach: current status and future perspective

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract, with the majority found in the stomach. Surgical resection of the primary gastric GISTs with complete resection margin has been the forefront of curative treatment. The indications for surgical resection are usually related to symptomatic gastric GISTs at presentation. Primary gastric GISTs resection performed conventionally through an open surgery can now be frequently achieved by minimal invasive surgery with similar oncological outcome. Surgeon's selection of the type of surgical techniques such as open, laparoscopic and endoscopic resections depends on the site, size and local invasion of gastric GISTs to the adjacent organ. Similarly those factors dictate the extent of gastric resections in the form of wedge, partial or total gastrectomy. All these inherent tumor factors (size and mitotic index), patient factors (older age, male) and surgical factors (incomplete resection margin, tumor rupture or spillage) play an important role in stratifying the malignant potential risk of primary gastric GISTs and their chances of recurrence. The understanding of gene mutation driving the growth of GISTs and the discovery of tyrosine kinase inhibitors (TKIs) has altered the surgical management of advanced and metastatic GISTs. Multi-modal therapy incorporating the surgical resection of GISTs and utilizing the molecular targeted therapy in the adjuvant, neoadjuvant and palliative settings can offer optimal personalized outcome and prolong patient's overall survival (OS).

Endoscopic ultrasound with tissue sampling is accurate in the diagnosis and subclassification of gastrointestinal spindle cell neoplasms

Background and Objectives:

Mesenchymal (spindle cell) neoplasms (SCN) of the gastrointestinal (GI) tract are an important subtype of subepithelial lesions that need subclassification to assess their malignant potential. Reported success rates of accurate subclassification with endoscopic ultrasound (EUS)-guided biopsies are variable. Our goal was to analyze our experience using EUS-guided TruCut biopsy (EUS-TCB) in the majority of patients.

Methods:

Retrospective analysis in patients who underwent EUS with biopsies for suspected SCN at our tertiary referral center between 2004 and 2013.

Results:

A total of 146 patients with suspected SCN underwent EUS with tissue acquisition. Thirteen patients were excluded from analysis because tissue acquisition established a definite diagnosis other than SCN. In the remaining 133 patients, tissue acquisition was diagnostic of SCN in 118 (88.7%) and nondiagnostic in 15 (11.3%). Subclassification based on immunohistochemistry (IHC) was possible in 109 of the 133 cases (81.9%). The final diagnosis was GI stromal tumor in 64, leiomyoma in 39, and schwannoma in 6 cases. The percentage of patients who were subclassified by the various EUS-guided techniques together was 72.18%, and the percentage of patients who were subclassified specifically with EUS-TCB was 61.65%. Tissue specimens that enabled a specific diagnosis based on histological or cytological characteristics in conjunctions with IHC were obtained with EUS core biopsy in 83 (TCB in 82 and ProCore needle biopsy in 1), fine-needle aspiration in 13, mucosal resection in 10, and forceps biopsies (bite-on-bite) in 3 cases.

Conclusion:

EUS with endoscopic tissue acquisition is accurate in the diagnosis and subclassification of SCN. In experienced hands, the EUS-TruCut needle is a valuable tool with a high success rate for this indication.

Initial experience with a novel EUS-guided core biopsy needle (SharkCore): results of a large North American multicenter study

BACKGROUND AND AIMS

The ability to safely and effectively obtain sufficient tissue for pathologic evaluation by using endoscopic ultrasound (EUS) guidance remains a challenge. Novel designs in EUS needles may provide for improved ability to obtain such core biopsies. The aim of this study was to evaluate the diagnostic yield of core biopsy specimens obtained using a novel EUS needle specifically designed to obtain core biopsies.

PATIENTS AND METHODS

Multicenter retrospective review of all EUS-guided fine-needle biopsies obtained using a novel biopsy needle (SharkCore FNB needle, Medtronic, Dublin, Ireland). Data regarding patient demographics, lesion type/location, technical parameters, and diagnostic yield was obtained.

RESULTS

A total of 250 lesions were biopsied in 226 patients (Median age 66 years; 113 (50 %) male). Median size of all lesions (mm): 26 (2 - 150). Overall, a cytologic diagnosis was rendered in 81 % specimens with a median number of 3 passes. When rapid onsite cytologic evaluation (ROSE) was used, cytologic diagnostic yield was 126/149 (85 %) with a median number of 3 passes; without ROSE, cytologic diagnostic yield was 31/45 (69 %, P = 0.03) with a median number of 3 passes. Overall, a pathologic diagnosis was rendered in 130/147 (88 %) specimens with a median number of 2 passes. Pathologic diagnostic yield for specific lesion types: pancreas 70/81 (86 %), subepithelial lesion 13/15 (87 %), lymph node 26/28 (93 %). Ten patients (10/226, 4 %) experienced adverse events: 4 acute pancreatitis, 5 pain, 1 fever/cholangitis.

CONCLUSIONS

Initial experience with a novel EUS core biopsy needle demonstrates excellent pathologic diagnostic yield with a minimum number of passes.

The diagnostic value of endoscopic ultrasonography and contrast-enhanced harmonic endoscopic ultrasonography in gastrointestinal stromal tumors

Objective:

To evaluate the diagnostic value of endoscopic ultrasonography (EUS) and contrast-enhanced harmonic (CEH) EUS in patients with gastrointestinal stromal tumors (GISTs).

Patients and Methods:

About 19 patients with suspected GISTs underwent EUS and CEH-EUS before tumor resection. The malignant potential was assessed according to the modified Fletcher classification system. Patients were divided into lower (Group I) and higher (Group II) malignant potential group. The clinical characteristics and EUS/CEH-EUS features were compared between two groups.

Results:

The tumor size in Group II was significantly larger than that in Group I (14.6 ± 5.8 mm vs. 32.1 ± 8.4 mm, P < 0.05). Heterogeneous echogenicity was observed in 4 (4/8) cases in Group II and none in Group I (P < 0.05). Irregular intratumoral vessels were detected in 6 cases in Group II and none in Group I (P < 0.05). The sensitivity and specificity of irregular vessel detection for discriminating higher from lower malignant potential GISTs were 75% and 100%, respectively. The positive predictive value and negative predictive value of detection of irregular vessels to high malignant potential GISTs were 33% and 100%, respectively.

Conclusion:

Detection of irregular intratumoral vessels can predict higher malignant potential before tumor resection. The tumor size and echogenicity are assistant factors for malignant potential assessment. Endoscopic resection is an efficacious treatment with good security for appropriate patients.

Diagnostic efficacy of endoscopic ultrasound-guided needle sampling for upper gastrointestinal subepithelial lesions: a meta-analysis

BACKGROUND

An increasing number of studies have been conducted on the use of endoscopic ultrasound (EUS)-guided needle sampling for upper gastrointestinal subepithelial lesions (SEL). However, reported diagnostic efficacy varies greatly.

OBJECTIVE

To summarize up current evidences on the diagnostic efficacy of EUS-guided needle sampling for upper GI SEL.

METHOD

A reproducible strategy was used to search four databases. Search results were evaluated for eligibility, and the quality of eligible studies was assessed by QUADAS-2. Pooled efficacy of EUS-guided needle sampling in upper GI SEL was calculated. Procedure-related complications, diagnostic errors, and independent factors related to a higher success rate were also recorded and analyzed.

RESULTS

Seventeen studies, comprising 978 attempts of EUS-guided needle sampling, were included in a meta-analysis. Pooled diagnostic rate of EUS-guided needle sampling was 59.9 %, with a heterogeneity I (2) of 55.2 %. Subgroup analysis showed no difference in diagnostic rate among fine needle aspiration (FNA), trucut needle biopsy (TCB), and fine needle biopsy (FNB), or among 19-, 22-, and 25-G needles. Subgroup analysis and meta-regression suggested that the cell block method might be correlated with a higher diagnostic rate. Few severe complications were reported. Diagnosis errors were rare.

CONCLUSION

EUS-guided needle sampling is a safe, but only moderately effective method for pathology diagnosis of upper GI SEL. Choice of FNA/TCB/FNB, or 19 G/22 G/25 G does not seem to alter the overall diagnostic rate.

Endoscopic ultrasound-guided fine needle tissue acquisition biopsy samples do not allow a reliable proliferation assessment of gastrointestinal stromal tumours

BACKGROUND

Current prognostication of gastrointestinal stromal tumours is validated on/applies to resected tumours, mainly because surgery is recommended whenever possible. However, pre-treatment prognostication is increasingly warranted, considering the follow-up strategy recently admitted for expectedly low-risk tumours and the possible distinctive molecular features/spontaneous regression of some small cases.

AIMS

To investigate whether endoscopic ultrasound-guided fine-needle tissue acquisition-biopsies reflect prognosticators of resected gastrointestinal stromal tumours, for possibly developing reliable pre-treatment prognostic criteria.

METHODS

The applicability/reliability of mitotic index/5mm(2) and MIB1 proliferative index/1000 cells were tested in 35 endoscopic ultrasound-guided fine-needle tissue acquisition-biopsies diagnosed as gastrointestinal stromal tumour, subsequently resected without intervening therapy, consecutively collected in thirty months. Size and mitotic/proliferative indexes were compared with resection specimens. The feasibility of bioptic genotyping was also tested.

RESULTS

35 patients were studied (45.7% males; mean age 61.6 years, range 26-83 years). Mitotic/proliferative indexes were determinable in 68.6%/88.6% of biopsies, respectively; they were nevertheless underestimated, as happened with endoscopic ultrasound-determined tumour size. Bioptic genotyping revealed reliable.

CONCLUSIONS

Endoscopic ultrasound-guided fine-needle tissue acquisition does not reliably reflect gastrointestinal stromal tumours' proliferation and size. Alternative parameters should be validated for a pre-surgical prognostic classification. Considering the emerging potentially prognostic genetic markers in gastrointestinal stromal tumours, the reliability of bioptic genotyping is a promising result.

Tips to overcome technical challenges in EUS-guided tissue acquisition

The diagnostic yield of EUS-FNA depends on several factors, such as the experience of the endosonographer, the characteristics of the lesion, the clinical status of the patient, the size and type of needles, the methods of specimen preparation, as well as cytopathologist expertise. The endosonographic technique can be improved when several tips and tricks useful to overcome challenges of FNA are known. Technical challenges of FNA are related to the characteristics of the lesion and its surroundings, sonographic imaging, and limitations related to the needle. Several tips and tricks necessary to overcome them are presented in this review.

Diagnosis of an accessory spleen mimicking a gastric submucosal tumor using endoscopic ultrasonography-guided fine-needle aspiration

Accessory spleen can be mistaken as a gastric subepithelial mass, and may not be differentiated in CT or endoscopic ultrasonography (EUS). A gastric subepithelial mass was detected on routine endoscopy in a 39-year old woman with history of splenectomy. In subsequent CT and EUS, the subepithelial mass was located on the fourth layer of the stomach. To make a definite diagnosis, EUS-guided fine needle aspiration (FNA) was performed, and a splenic tissue was demonstrated in histologic examination. EUS-guided FNA can be beneficial in the diagnosis of accessory spleen which mimics a gastric subepithelial mass.

Factors affecting the diagnostic accuracy of endoscopic ultrasonography-guided fine-needle aspiration (EUS-FNA) for upper gastrointestinal submucosal or extraluminal solid mass lesions

AIM

A number of potential variables are associated with the diagnostic accuracy of endoscopic ultrasonography-guided fine-needle aspiration (EUS-FNA). The aim of this study was to evaluate factors affecting the diagnostic accuracy of EUS-FNA for upper gastrointestinal submucosal or extraluminal solid lesions.

METHODS

Patients with such lesions who underwent EUS-FNA between January 2009 and December 2010 were studied retrospectively. Needles of 22, 25 and 19 gauge were used. The associations between the EUS-FNA results and factors such as mass location, mass size, needle size, number of needle passes, combined histologic-cytologic analysis and final diagnosis were analyzed.

RESULTS

A total of 170 EUS-FNA procedures were performed in 158 patients with upper gastrointestinal submucosal or extraluminal solid lesions. The overall accuracy of EUS-FNA was 86.5% (147/170). The diagnostic accuracy with three or more needle passes was higher than with less than 3.0 needle passes (90.0%, 108/120 vs 78.0%, 39/50; P < 0.05). Mass location, mass size, and final diagnosis were not associated with EUS-FNA accuracy. Combined cytologic-histologic analysis had significantly higher diagnostic accuracy than either cytologic or histologic analysis alone (P < 0.001). In a subgroup of 90 patients, both 22 and 25 gauge needles were used for EUS-FNA. The overall diagnostic accuracy was similar for 25 gauge needles and 22 gauge needles (80.0% vs 78.9% P = 1.000) in this subgroup.

CONCLUSION

Overall, 25 and 22 gauge needles have a similar diagnostic accuracy. Our results suggest that 3.0 or more needle passes and combined cytologic-histologic analysis enhance the diagnostic accuracy of EUS-FNA.

Endoscopic ultrasound-guided fine needle aspiration in submucosal lesion

A submucosal lesion, more appropriately a subepithelial lesion, is hard to diagnose. Endoscopic ultrasonography is good to differentiate the nature of submucosal lesion. For definite diagnosis, tissue acquisition from submucosal lesion is necessary, and many methods have been introduced for this purpose mainly by endoscopic ultrasonography, such as endoscopic ultrasound-guided fine needle aspiration (EUS-FNA), EUS-guided Trucut Biopsy (TCB), and EUS-guided fine needle biopsy (FNB). For EUS-FNA, adequate processing of specimen is important, and for proper diagnosis of EUS-FNA specimen, both cytologic and histologic examinations, including immunohistochemical stains, are important. All gastrointestinal stromal tumors have some degree of malignant potential, so there have been a lot of efforts and methods to increase diagnostic yields of submucosal lesion. We herein review the current hot topics on EUS-FNA for submucosal tumor, such as needles, on-site cytopathologists, immunohistochemical stains, EUS-TCB, EUS-FNB, Ki-67 labelling index, DOG1, and combining EUS-FNA and EUS-TCB.