Endoscopic sonographically guided fine-needle aspiration yield in submucosal tumors of the gastrointestinal tract

Diagnostic yield of endoscopic and EUS-guided biopsy techniques in subepithelial lesions of the upper GI tract: a systematic review

BACKGROUND AND AIMS

Obtaining adequate tissue samples in subepithelial lesions (SELs) remains challenging. Several biopsy techniques are available, but a systematic review including all available techniques to obtain a histologic diagnosis of SEL is lacking. The aim of this study was to evaluate the diagnostic yield and adverse event rates of endoscopic biopsies, EUS-guided FNA (EUS-FNA), EUS-guided fine-needle biopsy (FNB) (EUS-FNB), and mucosal incision-assisted biopsy (MIAB) for SELs in the upper GI tract.

METHODS

A search strategy in multiple databases was performed. The primary outcome was diagnostic yield, defined as the percentage of procedures in which histology was obtained and resulted in a definitive histopathologic diagnosis. Secondary outcome measures included reported procedure-related adverse events, which were graded according to the AGREE (Adverse Events in Gastrointestinal Endoscopy) classification.

RESULTS

A total of 94 original articles were included. Studies were classified per endoscopic technique to obtain histopathology. This resulted in 8 included studies for endoscopic biopsy methods, 55 studies for EUS-FNA, 33 studies for EUS-FNB, and 26 studies for MIAB. Pooled rates for diagnostic yield were 40.6% (95% confidence interval [CI], 30.8-51.2) for endoscopic biopsy, 74.6% (95% CI, 69.9-78.7) for EUS-FNA, 84.2% (95% CI, 80.7-87.2) for EUS-FNB, and 88.2% (95% CI, 84.7-91.1) for MIAB. Reported procedure-related adverse events graded AGREE II or higher were 2.8% to 3.9% for endoscopic biopsies, 1.0% to 4.5% for EUS-FNA, .9% to 7.7% for EUS-FNB, and 1.9% to 7.9% for MIAB.

CONCLUSIONS

Based on the available evidence, MIAB and EUS-FNB seem to be most effective in terms of achieving a high diagnostic yield, with similar rates of adverse events.

Magnetically Actuated Soft Capsule Endoscope for Fine-Needle Biopsy

Wireless capsule endoscopes have revolutionized diagnostic procedures in the gastrointestinal (GI) tract by minimizing discomfort and trauma. Biopsy procedures, which are often necessary for a confirmed diagnosis of an illness, have been incorporated recently into robotic capsule endoscopes to improve their diagnostic functionality beyond only imaging. However, capsule robots to date have only been able to acquire biopsy samples of superficial tissues of the GI tract, which could generate false-negative diagnostic results if the diseased tissue is under the surface of the GI tract. To improve their diagnostic accuracy for submucosal tumors/diseases, we propose a magnetically actuated soft robotic capsule robot, which takes biopsy samples in a deep tissue of a stomach using the fine-needle biopsy technique. We present the design, control, and human-machine interfacing methods for the fine-needle biopsy capsule robot. Ex vivo experiments in a porcine stomach show 85% yield for the biopsy of phantom tumors located underneath the first layers of the stomach wall.

Concise review on the comparative efficacy of endoscopic ultrasound-guided fine-needle aspiration vs core biopsy in pancreatic masses, upper and lower gastrointestinal submucosal tumors

Endoscopic ultrasound (EUS)-guided fine needle aspiration with or without biopsy (FNA/FNB) are the primary diagnostic tools for gastrointestinal submucosal tumors. EUS-guided fine needle aspiration (EUS-FNA) is considered a first line diagnostic method for the characterization of pancreatic and upper gastrointestinal lesions, since it allows for the direct visualization of the collection of specimens for cytopathologic analysis. EUS-FNA is most effective and accurate when immediate cytologic assessment is permitted by the presence of a cytopathologist on site. Unfortunately, the accuracy and thus the diagnostic yield of collected specimens suffer without this immediate analysis. Recently, a EUS-FNB needle capable of obtaining core samples (fine needle biopsy, FNB) has been developed and has shown promising results. This new tool adds a new dimension to the diagnostic and therapeutic utility of this technique. The aim of the present review is to compare the efficacy of EUS-FNA to that afforded by EUS-FNB in the characterization of pancreatic masses and of upper and lower gastrointestinal submucosal tumors.

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.

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.

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.

The clinical usefulness of endoscopic ultrasound-guided fine needle aspiration and biopsy for rectal and perirectal lesions

BACKGROUND/AIMS

Endoscopic ultrasound-guided fine needle aspiration and/or biopsy (EUS-FNA/B) have been used to diagnose subepithelial tumors (SETs) and extraluminal lesions in the gastrointestinal tract. Our group previously reported the usefulness of EUS-FNA/B for rectal and perirectal lesions. This study reports our expanded experience with EUS-FNA/B for rectal and perirectal lesions in terms of diagnostic accuracy and safety. We also included our new experience with EUS-FNB using the recently introduced ProCore needle.

METHODS

From April 2009 to March 2014, EUS-FNA/B for rectal and perirectal lesions was performed in 30 consecutive patients. We evaluated EUS-FNA/B performance by comparing histological diagnoses with final results. We also investigated factors affecting diagnostic accuracy.

RESULTS

Among 10 patients with SETs, EUS-FNA/B specimen results revealed a gastrointestinal stromal tumor in 4 patients and malignant lymphoma in 1 patient. The diagnostic accuracy of EUS-FNA/B was 50% for SETs (5/10). Among 20 patients with non-SET lesions, 8 patients were diagnosed with malignant disease and 7 were diagnosed with benign disease based on both EUS-FNA/B and the final results. The diagnostic accuracy of EUS-FNA/B for non-SET lesions was 75% (15/20). The size of lesions was the only factor related to diagnostic accuracy (P=0.027). Two complications of mild fever and asymptomatic pneumoperitoneum occurred after EUS-FNA/B.

CONCLUSIONS

The overall diagnostic accuracy of EUS-FNA/B for rectal and perirectal lesions was 67% (20/30). EUS-FNA/B is a clinically useful method for cytological and histological diagnoses of rectal and perirectal lesions.

Factors Associated with Inadequate Tissue Yield in EUS-FNA for Gastric SMT

Aims. Our aim was to identify the factors that made the specimens inadequate and nondiagnostic in endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) biopsy of suspected submucosal tumors (SMTs). Methods. From August 2001 to October 2009, 47 consecutive patients with subepithelial hypoechoic tumors originating in the fourth sonographic layer of the gastric wall suspected as GIST by standard EUS in Chiba University hospital underwent EUS-FNA for histologic diagnosis. We evaluated patient age, sex, location of lesion, size, pattern of growth in a stomach, and pattern of echography retrospectively. We defined a case of gaining no material or an insufficient material for immunohistological diagnosis as nondiagnostic. Results. The diagnostic yield of EUS-FNA for the diagnosis of gastric SMTs was 74.5%. Multivariate logistic regression analysis identified that age of under 60 years (compared with patients older than 60 years: odds ratio [OR] = 11.91, 95% confidence interval [CI] = 1.761-80.48) and location of SMT at lower third area (compared with upper or middle third area: OR = 10.62, 95% CI = 1.290-87.42) were the predictive factors for inadequate tissue yield in EUS-FNA. Conclusions. The factors associated with inadequate tissue yield in EUS-FNA were younger age and the location of lesion at lower third area in stomach.

Diagnostic utility of EUS-guided FNA in patients with gastric submucosal tumors

BACKGROUND

Submucosal tumors (SMTs) comprise both benign and malignant lesions, and most of the gastric lesions tend to be malignant. The addition of EUS-guided FNA (EUS-FNA) has the potential to improve this distinction, but published series are limited.

OBJECTIVE

To evaluate the yield of EUS-FNA in gastric SMTs with referral to a criterion standard final diagnosis.

DESIGN

Retrospective study.

SETTING

Tertiary-care referral center.

PATIENTS

This study involved 141 consecutive patients with gastric SMTs, who underwent EUS-FNA from January 2000 to December 2008. Immunohistochemical staining with c-kit, CD34, actin, and S-100 antibodies was done if a spindle cell tumor was found. Based on FNA sample adequacy, and whether a specific diagnosis could be established, EUS-FNA results were categorized as diagnostic, suggestive, or nondiagnostic. The criterion standards for final diagnosis were the surgical histopathological results or the follow-up course for malignant, inoperable cases.

INTERVENTION

EUS-FNA.

MAIN OUTCOME MEASUREMENTS

Diagnostic yield of EUS-FNA and factors related to sampling adequacy for cytological and immunohistochemical evaluation.

RESULTS

A total of 141 patients (52% female, mean age 56.7 years) underwent EUS-FNA (range 1-5 passes). The overall results of EUS-FNA were diagnostic, suggestive, and nondiagnostic in 43.3%, 39%, and 17.7% of cases, respectively. Adequate specimens were obtained in 83% of cases, and 69 cases (48.9%) had a definitive final diagnosis. The most common gastric SMT was GI stromal tumor (59.5%). EUS-FNA results were 95.6% accurate (95% confidence interval [CI], 87.5%-99%) for the final diagnosis and 94.2% (95% CI, 85.6%-98.1%) accurate for differentiating potentially malignant lesions. A heterogeneous echo pattern was the only independent predictor for sampling adequacy (adjusted odds ratio 6.15; P = .002). There were no procedure-related complications.

LIMITATIONS

Possibility of selection bias.

CONCLUSION

EUS-FNA is an accurate method for diagnosis of gastric SMTs and for differentiating malignant lesions.

Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA): experience of an academic centre in the USA

OBJECTIVES

Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) has become widely accepted as an effective modality for obtaining tissue for primary diagnosis and staging. We have been using EUS-FNA since July 2001 and herein we summarize our experience over a 5-year period.

METHODS

A computer-based search for in-house EUS-FNA was performed in the pathology database from July 2001 to October 2006. To calculate the sensitivity, specificity and accuracy of EUS-FNA, the cytology diagnosis was compared with the surgical follow-up.

RESULTS

A total of 951 EUS-FNAs were performed during the study period and included 279 pancreatic solid lesions, 186 pancreatic cyst lesions, 249 lymph node aspirations, 111 gastrointestinal (GI) tract submucosal lesions, and 126 miscellaneous lesions. EUS-FNA had a very high sensitivity and accuracy for solid pancreatic lesions (94.7 and 97.7%, respectively), low sensitivity and accuracy but high specificity (47, 64.8 and 95%, respectively) for cystic lesions. Cyst fluid carcinoembryonic (CEA) levels were significantly higher in mucinous neoplasms than non-neoplastic cysts. EUS-FNA also had very high sensitivity and specificity for detecting metastatic carcinoma in lymph nodes (95 and 100%, respectively). GI submucosal spindle cell tumours were further classified with immunohistochemical stains performed either on a cell block or a core biopsy obtained via EUS guidance.

CONCLUSIONS

EUS-FNA has a very high sensitivity and accuracy for pancreatic solid lesions, but the sensitivity for cystic lesions is generally low. Cyst fluid chemical analysis for CEA is helpful, but the overlap between mucinous neoplasm and non-neoplastic cysts is significant. Recognizing GI contamination is important and immunohistochemical stains are useful for GI submucosal spindle cell lesions.

Gastric Metastasis from Ovarian Adenocarcinoma Presenting as a Submucosal Tumor without Ulceration

Metastatic gastric cancer is extremely rare and gastric metastasis from ovarian adenocarcinoma has rarely been reported. All of the previously reported metastatic lesions presented as an ulcerative lesions. We report a case of 49-year-old woman in which gastric metastasis from ovarian adenocarcinoma presented as a submucosal tumor without ulceration on endoscopic examination. Gastrointestinal stromal tumor was suspected on endoscopic ultrasound (EUS) examination. It was confirmed histopathologically as metastatic ovarian adenocarcinoma after endoscopic submucosal dissection (ESD) with enucleation. Submucosal tumor of the stomach in patients with ovarian carcinoma should not be overlooked and ESD with enucleation may be a viable option when EUS with fine needle aspiration is not available.

EUS-guided FNA for the diagnosis of GI stromal cell tumors: sensitivity and cytologic yield

BACKGROUND

EUS-guided FNA has been well documented to aid in the diagnosis of subepithelial lesions by providing cytologic material. Studies to date evaluating the sensitivity of EUS-FNA for the diagnosis of GI stromal cell tumors (GIST) have been small, and few have relied on surgical histologic diagnosis as the reference standard.

OBJECTIVE

Our purpose was to determine the diagnostic yield and sensitivity of EUS-FNA for the diagnosis of GIST and to identify EUS features of GIST that are predictive of the ability to obtain adequate tissue by EUS-FNA.

DESIGN

All patients with histologically confirmed, c-kit-positive GIST who underwent EUS-FNA from 1998 to 2006 were reviewed. EUS images were examined for mass size, shape, location, wall layer, heterogeneity, echogenicity, cystic spaces, lobulation, ulceration, and central umbilication. Needle gauge, number of needle passes, and presence of a cytologist during the EUS-FNA were recorded.

RESULTS

A total of 37 patients (29 with diagnostic FNA cytology; 8 with nondiagnostic cytology) met the inclusion criteria. The diagnostic yield and sensitivity of EUS-FNA cytology for the diagnosis of GIST was 78.4% (29/37). The sensitivity was 84.4% (27/32) for GISTs located in the stomach, but poor for lesions located in the duodenum because none of these tumors yielded diagnostic cytology (n = 3). An increase in size up to 10 cm, round/oval shape, and identification of the origin of GIST within a specific sonographic wall layer were statistically significant in their ability to predict adequate tissue yield.

CONCLUSIONS

The sensitivity of EUS-FNA cytology for the diagnosis of GIST is 78.4% and is influenced by size, location, shape, and layer of origin.

EUS-guided sampling of suspected GI stromal tumors

BACKGROUND

The diagnostic yield of EUS-guided FNA (EUS-FNA) of suspected GI stromal tumors (GIST) has not been assessed in large series.

OBJECTIVE

Our purpose was to determine the diagnostic yield of EUS-FNA of subepithelial lesions with EUS features suggestive of GIST.

DESIGN

Retrospective database review.

SETTING

Tertiary care referral center and an urban Veterans Administration hospital.

PATIENTS

Consecutive patients referred for EUS evaluation of upper GI subepithelial lesions of the fourth endosonographic layer who underwent EUS-FNA.

MAIN OUTCOME MEASUREMENTS

Proportion of patients whose cytopathologic examination was diagnostic (immunohistochemical stains establish a specific diagnosis), suspicious (spindle cells identified, quantity not sufficient for specific stains), or nondiagnostic.

RESULTS

A total of 112 patients (45.5% female, mean age 61.6 years) underwent EUS-FNA (mean number of FNA passes 5.3). Tumor location was as follows: stomach 62.5%, esophagus 30.4%, and duodenum 7.1%. EUS-FNA was diagnostic in 61.6%, suspicious (spindle cells) in 22.3%, and nondiagnostic in 16.1%. The histologic results were 31.3% GIST, 26.8% leiomyomas, 22.3% spindle cell neoplasms, 3.5 % neural tumors, and 16.1% nondiagnostic. Fifteen (12.5%) patients also underwent EUS-guided core needle biopsy needle sampling; 7 were diagnostic, 2 suspicious, and 6 nondiagnostic. Twenty-four (20.0%) patients underwent jumbo forceps sampling; 5 were diagnostic, 1 suspicious, and 18 nondiagnostic. There were no cases of diagnostic core needle biopsy after nondiagnostic FNA core needle biopsy. Jumbo forceps biopsy of ulcerated masses was diagnostic in 3 GISTs in which FNA was nondiagnostic. Univariate and multivariate analyses showed that no variable was associated with an increased diagnostic yield.

CONCLUSIONS

EUS-FNA sampling of subepithelial lesions was diagnostic in 61.6% and showed a spindle cell neoplasm ("suspicious") in another 22.3% (diagnostic yield 83.9%). Core needle biopsy needle sampling did not increase the yield, but in the setting of an ulcerated mass, forceps biopsy may be diagnostic.

Disease progression following imatinib failure in gastrointestinal stromal tumors: role of surgical therapy

Gastrointestinal stromal tumors (GISTs) represent the most common mesenchymal neoplasms of the GI tract. The optimal management of GISTs has been evolving rapidly over the past 5 years and depends on proper histopathologic and radiologic diagnosis as well as appropriate multidisciplinary medical and surgical treatments. Complete surgical resection of primary localized GIST with negative margins remains the best therapeutic option today. In the setting of locally advanced or metastatic disease, imatinib mesylate has emerged as the initial treatment of choice, administered either as cytoreductive or as definitive treatment. Surgery or ablative modalities in this setting are becoming increasingly employed, particularly when all disease becomes amenable to gross resection or destruction, or to manage complications arising from the disease following imatinib failure. We report on the surgical management of an unusual and clinically significant complication following progression of disease secondary to imatinib resistance. The role of surgical therapy in the management of GIST complications following resistance to imatinib and the integration of surgical and molecular therapy of locally advanced or metastatic GISTs are discussed.

Preoperative diagnosis of gastrointestinal stromal tumor by endoscopic ultrasound-guided fine needle aspiration

AIM: To evaluate the role of endoscopic ultrasonography-guided fine needle aspiration (EUS-FNA) in the preoperative diagnosis of gastrointestinal stromal tumor (GIST).

METHODS: From September 2002 to June 2006, Fifty-three consecutive EUS-FNAs of GI tract subepithelial hypoechoic tumors with continuity to proper muscle layer suspected as GIST by standard EUS were evaluated prospectively. The reference standards for the final diagnosis were surgery (n = 31), or clinical follow-up (n = 22). Additionally, immunophenotyping of specimens obtained by EUS-FNA and surgical resection specimens were compared.

RESULTS: In 2 cases puncture was not performed because of anatomical problems. The collection rate of adequate specimens from the GI tract subepithelial hypoechoic tumor with continuity to proper muscle layer was 82% (42/51). The diagnostic rate for the tumor less than 2 cm, 2 to 4 cm, and 4 cm or more were 71% (15/21), 86% (18/21), and 100% (9/9), respectively. In 29 surgically resected cases, the sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of EUS-FNA using immunohistochemical analysis of GIST were 100% (24/24), 80% (4/5), 96% (24/25), 100% (4/4), and 97% (28/29), respectively. No major complications were encountered.

CONCLUSION: EUS-FNA with immunohistochemical analysis is a safe and accurate method in the prethera-peutic diagnosis of GIST. It should be taken into consideration in decision making, especially in early diagnosis following minimal invasive surgery for GIST.

Imaging, morphologic, and immunohistochemical correlation in gastrointestinal stromal tumors

BACKGROUND

Gastrointestinal stromal tumors (GISTs) recently have been distinguished morphologically, immunohistochemically, and genetically from other gastrointestinal-tract spindle cell neoplasms. The objective of this study was to correlate clinical and imaging findings with morphology and immunohistochemistry to diagnose GISTs and to differentiate them from other spindle cell lesions in the gastrointestinal tract.

METHODS

The authors reviewed 9 patients who had tumors that were diagnosed as GIST by image-guided and endosonographic-guided fine-needle aspiration (FNA) with or without core biopsy (7 stomach tumors and 2 intraabdominal tumors). The male:female ratio was 3:6, and the patients ranged in age from 38 years to 80 years. Onsite evaluation, preliminary cytologic evaluation, and immunohistochemistry were provided for 6 patients. Immunostains were performed, depending on sample size, on aspirates and/or core biopsies.

RESULTS

On imaging studies, most tumors were smooth and homogenous, consistent with GIST. Tumors ranged in size from 1.8 cm to 22 cm. The largest neoplasm showed solid/cystic and necrotic components. Aspirates consisted of spindle cell, neoplastic proliferation arranged in fascicles that exhibited focal, nuclear palisading; indistinct, cytoplasmic borders; and no significant atypia or mitosis. Focal epithelioid changes or cytologic atypia and mitoses were observed in 2 tumors. Immunostains revealed tumor expression of CD117 and/or CD34 in 5 of 6 tumors, expression of actin in 3 of 6 tumors, and expression of desmin in 1 of 6 tumors. All tumors were diagnosed as GIST (or consistent with GIST for tumors that lacked immunochemical analysis). Five patients underwent surgical excision, and the GIST diagnosis was confirmed in 3 patients, whereas 1 tumor proved to be neurofibroma, and another tumor was leiomyoma. No surgical follow-up was available for the remaining 4 patients, who had imaging and morphologic findings consistent with GIST.

CONCLUSIONS

In the setting of consistent clinical and radiologic findings, the combined use of cytomorphology and immunohistochemistry on FNA and/or core biopsy in most instances provides a reliable pathologic diagnosis of GIST. The need of sufficient material for performing ancillary studies and the usual impossibility of excluding malignancy are limitations of FNA cytology of GIST.

Review of endoscopic ultrasound-guided fine-needle aspiration cytology

This review, based on the Hennepin County Medical Center experience and review of the literature, vastly covers the up-to-date role of endoscopic ultrasonography (EUS) and EUS-guided fine-needle aspiration (FNA) in evaluating tumorous lesions of the gastrointestinal tract and adjacent organs. Emphasis is given to the tumoral and nodal staging of esophageal, pulmonary, and pancreatic cancer. This review also discusses technical, pathological, and gastroenterologic aspects and the role of the pathologist and endosonographer in the evaluation of these lesions, as well as the corresponding FNA cytology and differential diagnosis.

Gastric GI stromal tumors (GISTs): The role of surgery in the era of targeted therapy

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasm arising in the stomach. These tumors were previously classified as smooth muscle tumors, but in recent years it has become clear that they are clinically, pathologically, and molecularly distinct from other tumors and are much more common than previously appreciated. Historically, patients with primary localized or advanced GIST have been managed surgically, as there was no proven role of other treatment modalities such as radiation or chemotherapy. However, the field of GIST was revolutionized with the 1998 discovery that the vast majority of these tumors have oncogenic gain-of-function mutations of the KIT receptor tyrosine kinase. Follow-up studies have confirmed that KIT is both a useful diagnostic marker and an excellent therapeutic target. Imatinib, an inhibitor of KIT kinase activity, is now the standard front-line therapy for patients with advanced GIST. In this review, we discuss pathological and molecular features of gastric GISTs and review the historic and current roles of surgery in the treatment of patients with primary or metastatic GIST. The importance of a multi-disciplinary approach using both surgery and imatinib therapy is emphasized.