Fine-needle aspiration biopsy diagnosis of gastrointestinal stromal tumors using morphology, immunocytochemistry, and mutational analysis of c-kit

Clinical utility of endoscopic ultrasound-guided tissue acquisition for comprehensive genomic profiling of patients with biliary tract cancer, especially with intrahepatic cholangiocarcinoma

BACKGROUND/AIMS

Endoscopic ultrasound-guided tissue acquisition (EUS-TA) is a standard diagnostic method for biliary tract cancer (BTC), and samples obtained in this manner may be used for comprehensive genomic profiling (CGP). This study evaluated the utility of EUS-TA for CGP in a clinical setting and determined the factors associated with the adequacy of CGP in patients with BTC.

METHODS

CGP was attempted for 105 samples from 94 patients with BTC at the Aichi Cancer Center, Japan, from October 2019 to April 2022.

RESULTS

Overall, 77.1% (81/105) of the samples were adequate for CGP. For 22-G or 19-G fine-needle biopsy (FNB), the sample adequacy was 85.7% (36/42), which was similar to that of surgical specimens (94%, p=0.45). Univariate analysis revealed that 22-G or larger FNB needle usage (86%, p=0.003), the target primary lesions (88%, p=0.015), a target size ≥30 mm (100%, p=0.0013), and number of punctures (90%, p=0.016) were significantly positively associated with CGP sample adequacy.

CONCLUSIONS

EUS-TA is useful for CGP tissue sampling in patients with BTC. In particular, the use of 22-G or larger FNB needles may allow for specimen adequacy comparable to that of surgical specimens.

A Gastroenterologist's Approach to the Diagnosis and Management of Gastrointestinal Stromal Tumors

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal (GI) tract. These tumors have been shown to harbor oncogenic mutations of the c-kit tyrosine kinase receptor or platelet-derived growth factor receptor alpha (PDGFRA). Immunohistochemical analysis of GISTs allows for the differentiation of these tumors from other mesenchymal tumors of the GI tract such as leiomyomas and leiomyosarcomas. All GISTs have the potential to behave in a malignant fashion. Tumor location, size, and mitotic index are factors used to predict the risk of malignant behavior. Endoscopy and endoscopic ultrasound play a critical role in the diagnosis of GISTs and can yield important information to further risk-stratify tumors and determine management. This article provides a gastroenterologist's perspective on the diagnosis and management of GISTs.

Spindle cell neoplasms of the upper gastrointestinal tract, hepatobiliary tract, and pancreas by fine needle aspiration: A single institutional experience of 15 years with follow-up data

BACKGROUND

The diagnosis of spindle cell neoplasms (SCN) of the upper gastrointestinal (GI) tract, hepatobiliary tract, and pancreas detected by fine needle aspiration (FNA) is challenging. We describe a single-center experience of these samples with follow-up data and characterization of the morphologic findings.

METHODS

We retrospectively reviewed pathology records for all FNAs diagnostic for or suggestive of SCN on esophagus, stomach, small bowel, liver, and pancreas in a 15 year period. All cases with at least 6 month follow-up were included. Surgical material (biopsy or resection) was the diagnostic gold standard. All FNAs with subsequent surgical specimens were reviewed and assessed for cellularity, architectural features, and nuclear features.

RESULTS

In 15 years, 5101 FNAs of the upper GI tract, hepatobiliary tract, and pancreas were performed. SCN was diagnosed in 98 (2%) patients. Seventy-two patients had definitive pathologic diagnoses: 68 were neoplastic and four were non-neoplastic. Cytomorphologic review in relationship to final diagnosis revealed three statistically significant features: low cellularity favors a benign process (P = .00544), epithelioid nuclear morphology favors malignancy (P = .00278), and identification of perinuclear vacuoles favors a diagnosis of GIST over non-GIST SCN (P = .04236).

CONCLUSIONS

Among cases with follow-up, final pathologic diagnoses were SCN in 94% of cases diagnosed as SCN on FNA of upper GI, hepatobiliary tract, and pancreas. Although some cytomorphologic criteria are more suggestive of malignancy, arriving at a specific diagnosis relies on collaboration of clinical, radiologic, cytomorphologic, and immunohistochemical data.

Endoscopic ultrasound-guided fine needle aspiration cytology diagnosis of upper gastrointestinal tract mesenchymal tumors: Impact of rapid onsite evaluation and correlation with histopathologic follow-up

BACKGROUND

Mesenchymal tumors (MTs) of upper gastrointestinal tract (UGIT) can show morphologic overlap thus posing a diagnostic challenge. This study evaluated the role of endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) cytology in the diagnosis of UGIT-MTs and impact of rapid onsite evaluation (ROSE).

METHODS

We retrospectively search our electronic database between January 2001 and August 2019 for cases that underwent EUS-FNA for a submucosal/or intramural upper GI tract mass forming lesions. Data pertinent to immunostain expression in UGIT-MTs was also collected.

RESULTS

We identified 139 cases, of which 72 cases had subsequent surgical resection. The cytologic diagnoses included nondiagnostic, negative, atypical, suspicious for neoplasm and positive for neoplasm (PFN) in 11, 7, 11, 10, and 100 cases, respectively. Diagnosis of PFN was rendered in 51 of 69 cases with ROSE (74%) and in 49 of 70 cases without ROSE (70%). However, the cases with ROSE had a higher percentage of cases being precisely classified than without ROSE (86% vs 61%, P < .05). On comparison of cytologic cases with cell block (CB) (n = 118) and without CB (n = 21), ROSE was performed in 67 (57%) and 2 (10%) cases, respectively (P < .01). All the cases with diagnosis of PFN were confirmed on subsequent surgical resection.

CONCLUSION

EUS-FNA has a diagnostic yield of 72% for UGIT-MTs. ROSE could improve diagnostic performance by further classifying MTs, probably via securing adequate lesional material for cell block for additional ancillary testing and precise diagnosis.

Mesenchymal neoplasms of the tubular gut and adjacent structures: experience with EUS-guided fine-needle aspiration cytopathology

INTRODUCTION

Unlike epithelial malignancies, mesenchymal neoplasms arising within the tubular gut are less often encountered in endoscopic ultrasound-guided (EUS) fine-needle aspiration biopsies (FNABs). Nonetheless, preoperative diagnosis of such neoplasms has important therapeutic and prognostic value. We report our experience with this category of neoplasms from the past decade.

MATERIALS AND METHODS

We performed a 10-year retrospective search at our respective institutions to identify EUS-guided FNAB cases of mesenchymal neoplasms arising from the tubular gut wall and closely adjacent structures. Cytopathologic diagnoses were compared to corresponding surgical pathology (SP) when available. Cases with either no confirmatory cell block (CB) immunohistochemical (IHC) staining, or no SP were excluded.

RESULTS

Two-hundred eighty-two cases (M:F = 1:1; age range: 25-94 years, mean age = 60 years) of EUS-guided FNAB from the tubular gut met our criteria. Onsite adequacy was performed on nearly all cases. Case numbers: 209 gastrointestinal stromal tumors (GIST), 58 smooth muscle neoplasms, and 15 miscellaneous neoplasms. Of these, 188 (67%) had SP follow-up. We found that 258 (91%) aspirates had a correct specific diagnosis, 3 (1%) were nondiagnostic, 18 (6%) had indeterminate diagnoses, and 3 (1%) had incorrect diagnoses (2 leiomyosarcomas mistaken as leiomyoma, and 1 fibrosclerotic lesion mistaken as inflammatory pseudotumor). Of 94 cases with no SP, all had a specific cytologic diagnosis based on confirmatory IHC staining from the CB including 61 GISTs, 29 smooth muscle neoplasms, and 4 miscellaneous tumors.

CONCLUSION

This study endorses the clinical utility of EUS-guided FNAB in the diagnosis of tubular gut mesenchymal neoplasms. A definitive and accurate diagnosis is possible in over 90% of cases, chiefly when cytomorphology is coupled with optimal cellularity and IHC from a concurrent CB. EUS-guided FNAB diagnosis of mesenchymal tubular gut neoplasms may play an important role in determining neoadjuvant therapy as targeted therapy evolves.

Applications of Ancillary Testing in the Cytologic Diagnosis of Soft Tissue Neoplasms

Soft tissue neoplasms are diagnostically challenging, although many advances in ancillary testing now enable accurate classification of fine-needle aspiration biopsies by detection of characteristic immunophenotypes (including protein correlates of molecular alterations) and molecular features. Although there are many useful diagnostic immunohistochemical markers and molecular assays, their diagnostic utility relies on correlation with clinical and morphologic features, judicious application, and appropriate interpretation because no single test is perfectly sensitive or specific. This review discusses applications of ancillary testing for commonly encountered soft tissue neoplasms in cytopathologic practice in the context of a pattern-based approach.

A quarter century of EUS-FNA: Progress, milestones, and future directions

Tissue acquisition using EUS has considerably evolved since the first EUS-FNA was reported 25 years ago. Its introduction was an important breakthrough in the endoscopic field. EUS-FNA has now become a part of the diagnostic and staging algorithm for the evaluation of benign and malignant diseases of the gastrointestinal tract and of the organs in its proximity, including lung diseases. This review aims to present the history of EUS-FNA development and to provide a perspective on the recent developments in procedural techniques and needle technologies that have significantly extended the role of EUS and its clinical applications. There is a bright future ahead for EUS-FNA in the years to come as extensive research is conducted in this field and various technologies are continuously implemented into clinical practice.

Yields and Utility of Endoscopic Ultrasonography-Guided 19-Gauge Trucut Biopsy versus 22-Gauge Fine Needle Aspiration for Diagnosing Gastric Subepithelial Tumors

Background/Aims

To evaluate the yields and utility of 19-gauge (G) Trucut biopsy (TCB) versus 22 G fine needle aspiration (FNA) for diagnosing gastric subepithelial tumors (SETs).

Methods

We retrieved data for 152 patients with a gastric SET larger than 2 cm who had undergone endoscopic ultrasonography (EUS)-guided 19 G TCB (n=90) or 22 G FNA (n=62). Relevant clinical, tumor-specific, and EUS procedural information was reviewed retrospectively.

Results

A specific diagnosis was made for 76 gastrointestinal stromal tumors (GISTs) and 51 non-GIST SETs. The diagnostic yield of TCB was greater than that of FNA (77.8% vs. 38.7%, p<0.001). The percentage of non-diagnostic specimens (suspicious and insufficient) was significantly lower in the TCB group (6.7% and 15.5%, respectively) than in the FNA group (22.6% and 38.7%, respectively; both p<0.001). TCB accurately diagnosed 90.9% of GISTs and 81.1% of non-GIST SETs, whereas FNA accurately diagnosed 68.8% of GISTs and 14.3% of non-GIST SETs. There were nine technical failures with TCB, and the rate of adverse events did not differ between the groups (TCB vs. FNA, 3.3% vs. 8.1%; p=0.27).

Conclusions

Nineteen-gauge TCB is safe and highly valuable for diagnosing gastric SETs larger than 2 cm if technical failure can be avoided.

Biospecimen repositories and cytopathology

Biospecimen repositories are important for the advancement of biomedical research. Literature on the potential for biobanking of fine-needle aspiration, gynecologic, and nongynecologic cytology specimens is very limited. The potential for biobanking of these specimens as valuable additional resources to surgically excised tissues appears to be excellent. The cervicovaginal specimens that can be used for biobanking include Papanicolaou-stained monolayer preparations and residual material from liquid-based cytology preparations. Different types of specimen preparations of fine-needle aspiration and nongynecologic specimens, including Papanicolaou-stained and Diff-Quik-stained smears, cell blocks. and dedicated passes/residual material from fine-needle aspiration stored frozen in a variety of solutions, can be used for biobanking. Because of several gaps in knowledge regarding the standard of operative procedures for the procurement, storage, and quality assessment of cytology specimens, further studies as well as national conferences and workshops are needed not only to create awareness but also to facilitate the use of cytopathology specimens for biobanking.

Molecular diagnostic testing of cytology specimens: current applications and future considerations

Molecular mechanisms of pathogenesis continue to be discovered, accelerating significant expansion of the spectrum of clinically useful molecular diagnostic tests and their incorporation into patient care algorithms. Currently, molecular assays facilitate identification of infectious processes, detection of specific constitutional and somatically acquired pathogenic mutations, guidance of therapy selection, and monitoring of treatment response and disease progression. The correlation of genomic test results with clinical, morphologic, and immunophenotypic findings has defined the practice of "precision medicine" with wide-reaching implications for health care. As novel promising techniques such as microarrays and next-generation sequencing are adopted by health care providers, new practice standards are being developed for incorporation into practice. Cytology specimens are good sources of high-quality nucleic acids. Although sometimes limited in quantity, in many cases such specimens are well suited for molecular diagnostic testing, which is capable of maximizing the number of tests from small amounts of sample. The pathologist continues to serve as a central resource for diagnostic testing and consultation regarding appropriate use of molecular tests. Understanding current methodologies, clinical utility of currently available nucleic acid tests, validation requirements for test implementation, quality assurance metrics, and future technology trends is essential to the practice of contemporary molecular pathology.

Comparison of 22-gauge aspiration needle with 22-gauge biopsy needle in endoscopic ultrasonography-guided subepithelial tumor sampling

OBJECTIVE. Endoscopic ultrasonography (EUS)-guided fine-needle aspiration (EUS-FNA) may facilitate tissue sampling for histopathological diagnosis of subepithelial tumors (SETs) in the gastrointestinal (GI) tract. However, immunohistochemistry is not always feasible using EUS-FNA samples due to the low quality of specimens often obtained by aspiration. This study aimed to compare the use of 22-gauge (G) EUS-guided fine-needle biopsy (EUS-FNB) with 22G EUS-FNA for core sampling used for histopathological examination, including immunohistochemistry, in patients with GI SETs. METHODS. Twenty-eight patients with GI SETs ≥2 cm in size were prospectively enrolled at five university hospitals in Korea between January and June 2013. They were randomized to undergo either EUS-FNB or EUS-FNA. RESULTS. A total of 22 patients was finally analyzed in this study: 10 and 12 patients underwent EUS-FNA and EUS-FNB, respectively. Compared to the EUS-FNA group, the EUS-FNB group had a significantly lower median number of needle passes to obtain macroscopically optimal core samples (4 vs. 2, p = 0.025); higher yield rates of macroscopically and histologically optimal core samples with three needle passes (30% vs. 92%, p = 0.006; 20% vs. 75%, p = 0.010, respectively); and a higher diagnostic sufficiency rate (20% vs. 75%, p = 0.010). No technical difficulties were encountered in either group. CONCLUSIONS. This study shows that EUS-FNB has a better ability to obtain histological core samples and a higher diagnostic sufficiency rate than EUS-FNA and that EUS-FNB is a feasible, safe, and preferable modality for adequate core sampling for histopathological diagnosis of GI SETs.

Cytomorphology of gastrointestinal stromal tumors and extra-gastrointestinal stromal tumors: A comprehensive morphologic study

BACKGROUND

The term gastrointestinal stromal tumors (GIST) is used to refer to those mesenchymal neoplasms of the gastrointestinal tract (GIT) which express CD117, a c-kit proto-oncogene protein.

AIMS

To study the cytological features of GIST and extra-gastrointestinal stromal tumors (EGIST), to correlate them with histology and to determine cytological indicators of malignancy.

MATERIALS AND METHODS

Cytological smears from patients diagnosed as GIST/EGIST on histology were retrieved. From Jan 2000 to July 2010, 26 GIST (13 primary, 12 metastatic, one recurrent) and seven EGIST (5 primary, one metastatic, one recurrent) cytologic samples from 27 patients were identified.

RESULTS

The patients included 20 males and 7 females with a mean age of 50.6 years. Tumor sites included stomach (5), duodenum (5), ileum (2), ileocecal (1), rectum (1), liver (9), retroperitoneum (5), mesentery (1), subcutaneous nodule (1), supra-penile lump (1), ascitic (1) and pleural fluids (1). The smears were cellular with cohesive to loosely cohesive thinly spread irregularly outlined cell clusters held together by thin calibre vessels. The tumor cells were mild to moderately pleomorphic, spindle to epithelioid with variable chromatin pattern and variable cytoplasm. Cellular dyscohesion, nuclear pleomorphism, intranuclear pseudoinclusions, prominent nucleoli, mitosis and necrosis were more prominent in malignant, metastatic and recurrent tumors.

CONCLUSIONS

GISTs show a wide spectrum of cytological features and the presence of mitosis, necrosis and nuclear pleomorphism can help in prediction of malignant behavior. Further, cytology is a very useful screening modality in patients of GIST and EGIST to detect early recurrence and metastasis at follow-up.

A phase I, first-in-human dose-escalation study of amuvatinib, a multi-targeted tyrosine kinase inhibitor, in patients with advanced solid tumors

PURPOSE

Amuvatinib is a novel orally administered tyrosine kinase inhibitor with in vitro pharmacological activity against mutant KIT, platelet-derived growth factor receptor alpha (PDGFRα), and Rad51. Amuvatinib was investigated in a first-in-human, single-agent, phase I, accelerated titration, dose-escalation trial ( clinicaltrials.gov identifier: NCT00894894) in patients with solid tumors refractory to prior therapies or for which no standard therapy existed.

METHODS

Twenty-two patients received amuvatinib dry powder capsules (DPC) from 100 to 1,500 mg daily in 28-day cycles. Safety, preliminary efficacy, pharmacologic activity, and pharmacokinetics were investigated.

RESULTS

No dose-limiting toxicities were reported with amuvatinib DPC up to 1,500 mg/day, given as one or in divided doses, for 1-6 cycles. No maximum tolerated dose was reached. Five patients had serious adverse events, all unrelated to treatment. Exposure levels were low and variable. One gastrointestinal stromal tumor (GIST) patient who previously failed imatinib and sunitinib had a 2-[18F]fluoro-2-deoxyglucose positron emission tomography response and clinical stable disease. A second GIST patient had decreased Rad51 expression in a skin punch biopsy on days 15 and 29.

CONCLUSIONS

Amuvatinib shows in vitro inhibitory activity against multiple human tyrosine kinases including mutant KIT and PDGFRα and in vivo activity in human xenograft models in mice. Amuvatinib is also active as a DNA repair protein Rad51 inhibitor following chemotherapy. In this study, the amuvatinib DPC formulation was well tolerated up to 1,500 mg/day. While exposures were low and variable, a transient response in a refractory GIST patient warrants further investigation into single-agent amuvatinib in refractory GIST.

Ecoendoscopia nas lesões subepiteliais do trato digestório: artigo de revisão

Lesões subepiteliais ou abaulamentos da mucosa são recobertas por mucosa normal e geralmente assintomáticas. Sua maioria é diagnosticada em exames radiológicos ou de endoscopia digestiva e podem corresponder a qualquer camada da parede do órgão (intramural) ou serem extramurais. Este artigo descreve estudos para análise da ultrassonografia após ecoendoscopia (USE) como método diagnóstico de elevada acurácia diante do achado de lesão subepitelial. Trata-se de trabalho de revisão de literatura sobre as características ecoendoscópicas das lesões subepiteliais e diferenciação em intra ou extramurais, camada de origem, ecogenicidade, vascularização, margens e dimensões, punção aspirativa por agulha fina (PAAF) ou biópsias com agulha do tipo trucut. Ambas as formas são aceitáveis) para análise histológica. A ultrassonografia endoscópica tem melhores índices de acurácia no diagnóstico da camada da parede gastrointestinal comprometida por lesões ou massas, além de estudar a ecogenicidade da lesão. A ultrassonografia endoscópica é um método seguro e detalhado, considerado o melhor exame de imagem para diagnóstico definitivo e programação terapêutica das lesões subepiteliais.

Cytologic findings of gastric schwannoma: a case report

Spindle cell lesions of the stomach are rare. They usually affect the submucosa or muscularis propria and therefore can be sampled by endoscopic fine needle aspiration. The most common tumor in this category is gastrointestinal stromal tumor (GIST), followed by leiomyoma and gastric schwannoma. Gastric schwannoma is a benign tumor of neuroectodermal origin that has overlapping morphologic/cytologic features with GIST and leiomyoma. Gastric schwannomas differ from peripheral schwannomas by lacking a capsule, Verocay bodies, Antoni B areas, and thick-walled vessels. They are characterized morphologically by poorly defined borders, cuffs of lymphoid tissue and a haphazard spindle cell proliferation. We present here the cytologic and histopathologic features of a gastric schwannoma. The tumor was composed of spindle cells with delicate eosinophilic cytoplasm and wavy nuclei, with an associated conspicuous lymphoid backdrop. The latter feature raised the possibility of a lymphoid lesion, a problem cytopathologists should be aware of.

Phase II escalation study of sorafenib in patients with metastatic renal cell carcinoma who have been previously treated with anti-angiogenic treatment

OBJECTIVE

To assess both clinical and biological efficacy and toxicity of sorafenib in patients with metastatic renal cell carcinoma (mRCC) previously treated with an anti-angiogenic vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitor.

METHODS

Sorafenib is an orally active multikinase inhibitor approved for the treatment of mRCC. Drug-focused translational research on tissues (i.e. B-RAF) and plasma (VEGFR-α, circulating endothelial cells, endothelial progenitor cells) was performed to define biological predictive and prognostic markers and their related kinetics. Patients with mRCC pretreated with an anti-angiogenic treatment, an Eastern Cooperative Oncology Group performance status (ECOG PS) of 0-2 and adequate organ function were eligible. Patients received sorafenib 400 mg twice a day continuously in 4-week cycles. Patients with no progressive disease at 12 weeks continued to receive sorafenib at the standard dose, whereas progressing patients received an increased dose (600 mg twice a day) with early disease restaging after 4 weeks. Patients who progressed at 600 mg twice a day went off study. Efficacy (overall tumour control) was assessed by Response Evaluation Criteria in Solid Tumors.

RESULTS

In all, 19 patients were entered. The baseline characteristics were as follows: ECOG PS 0-1 94.8%; median (range) age 62 (41-81) years; nephrectomy 100%; surgery for metastatic disease 26.4%; clear cell 79.1%; papillary cell 15.7%; sarcomatoid/high grade 5.2%; two or more metastatic sites 84%. Overall, 11 patients (58%) had disease control at 6 months without significant correlation between response to prior therapy and hypertension. Progression-free survival (PFS) of 8.3 months was observed. Of six patients for whom the dose was escalated due to early progression, three benefitted with PFS of >3 months. Three (15.7%) of 19 patients had a V600E mutation and one had a K601E mutation; PFS appeared to be substantially shorter in these patients compared with 15 patients with wild-type B-RAF (2.5 vs 9.1 month, P < 0.05). The most common toxicity (National Cancer Institute Common Toxicity Criteria, NCIC 3.0, all patients) was grade ≥1 diarrhoea and grade 2-3 hand-foot syndrome in 11 patients. Grade 3 mucositis was observed in one patient.

CONCLUSIONS

Sorafenib at doses of 400-600 mg twice a day continuously results in acceptable and well tolerated salvage treatment after VEGFR tyrosine kinase inhibitor failure. In progressive patients, treatment with a higher dose could be a valid option and B-RAF mutations may be an interesting predictive marker to be studied in a larger randomized trial.

Gastrointestinal stromal tumor: advances in diagnosis and management

CONTEXT

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasms of the gastrointestinal tract and should be differentiated from other mesenchymal tumors. They harbor specific activating mutations in the KIT or platelet-derived growth factor receptor α ( PDGFRA ) receptor tyrosine kinases, which makes them responsive to pharmacologic inhibitors, such as imatinib mesylate and sunitinib malate.

OBJECTIVES

To provide a comprehensive review of the pathogenesis of GIST and the underlying principles of targeted therapy, to review the salient histologic and immunohistochemical features that facilitate the distinction of GIST from other mesenchymal neoplasms of the gastrointestinal tract, and to present the prognostic parameters for risk stratification that guide clinical management.

DATA SOURCES

Review of the English literature through PubMed as well as personal experience. Photographs were taken from cases encountered at the Cleveland Clinic.

CONCLUSIONS

The discovery of the KIT -GIST connection has not only improved the diagnostic accuracy of GISTs but also provided us with a better understanding of the histogenesis and molecular pathogenesis of these neoplasms.

Basics of cytology

This overview is intended to give a general outline about the basics of Cytopathology. This is a field that is gaining tremendous momentum all over the world due to its speed, accuracy and cost effectiveness. This review will include a brief description about the history of cytology from its inception followed by recent developments. Discussion about the different types of specimens, whether exfoliative or aspiration will be presented with explanation of its rule as a screening and diagnostic test. A brief description of the indications, utilization, sensitivity, specificity, cost effectiveness, speed and accuracy will be carried out. The role that cytopathology plays in early detection of cancer will be emphasized. The ability to provide all types of ancillary studies necessary to make specific diagnosis that will dictate treatment protocols will be demonstrated. A brief description of the general rules of cytomorphology differentiating benign from malignant will be presented. Emphasis on communication between clinicians and pathologist will be underscored. The limitations and potential problems in the form of false positive and false negative will be briefly discussed. Few representative examples will be shown. A brief description of the different techniques in performing fine needle aspirations will be presented. General recommendation for the safest methods and hints to enhance the sensitivity of different sample procurement will be given. It is hoped that this review will benefit all practicing clinicians that may face certain diagnostic challenges requiring the use of cytological material.

Giant gastrointestinal stromal tumor presenting as a palpable abdominal mass: an unusual presentation

Gastrointestinal stromal tumors (GIST-) account for the majority of mesenchymal tumors arising within the gastrointestinal tract. GIST presenting as a palpable abdominal mass is extremely rare. We report four additional cases of a GIST presenting as an abdominal mass along with a pertinent review of the literature. Twenty five cases of GISTs presenting with an abdominal mass, including 4 cases discussed here, have been reported in the world literature since 2001. The mean duration of symptoms was 152.7 days. Twenty one of 25 (84%) patients received surgical resection. The mean tumor size was 17.2 cm, with an average mitotic index of 7.6 per 50 high power fields. Thirteen of 14 (92.9%) patients had a high-risk tumor. Five patients were disease-free at a mean followup of 11 months, 2 patients had stable disease and 2 patients had progressive disease, and one patient had a partial response. In conclusion, symptomatic patents have an increased incidence of high-risk tumors and metastases at presentation. Adjuvant therapy with imatinib improves disease-free survival in patients with large abdominal GIST tumors, but no change in overall survival was noted. Finally, GISTs should be considered in the differential diagnosis of an abdominal mass in an elderly patient.

Diagnosis of subepithelial tumors in the upper gastrointestinal tract by endoscopic ultrasonography

Endoscopic ultrasonography (EUS) is the most accurate procedure for detecting and diagnosing subepithelial tumors, due to its higher sensitivity and specificity than other imaging modalities. EUS can characterize lesions by providing information on echogenic origin, size, borders, homogeneity, and the presence of echogenic or anechoic foci. Linear echoendoscopes, and recently also electronic radial echoendoscopes, can be used with color Doppler or power Doppler to assess the vascular signals from subepithelial masses, and thus permit the differentiation of vascular structures from cysts, as well as the assessment of the tumor blood supply. However, the diagnostic accuracy of EUS imaging alone has been shown to be low in subepithelial lesions with 3rd and 4th layers. It is also difficult to differentiate exactly between benign and malignant tumors and to gain an accurate picture of histology using EUS. On the other hands, EUS guided fine needle aspiration (EUS-FNA) can provide samples for cytologic or histologic analysis. Hypoechoic lesions of the 3rd and the 4th EUS layers, more than in 1 cm diameter are recommended, and histologic confirmation using endoscopic submucosal resection or EUS-FNA should be obtained when possible. Therefore, EUS-FNA plays an important role in the clinical management of subepithelial tumors. Furthermore improvements in endoscopic technology are expected to be more useful modalities in differential diagnosis and discrimination between benign and malignant subepithelial tumors.

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

Recently, endoscopic ultrasonography-guided fine needle aspiration (EUS-FNA) has been applied for diagnosis of gastrointestinal submucosal tumors. There have been no definite criteria, however, for the adequate cytological diagnosis of gastrointestinal stromal tumor (GIST) in practice. To facilitate this a novel method is proposed that combines cytology and histology. For 49 cases of submucosal tumor of gastrointestinal tract, EUS-FNA was performed. The aspirated materials were processed for cytology and histology. Both cytological and histological findings were examined on immunocytochemical and immunohistochemical staining of c-kit. Of 49 cases, 40 (81.6%) proved adequate for cytological and/or histological examination. On cytology, cluster types were classified into type A (piled clusters with high cellularity showing a fascicular pattern), type B (thin layered clusters with high cellularity showing a fascicular pattern), and type C (mono-layered clusters or scattered cells). Types A and B were strongly associated with histological diagnosis of GIST. Type C clusters needed confirmation on c-kit positivity and histology. Thus, the combined cytology with newly defined features, and classification and histological diagnostic method for EUS-FNA materials can contribute to improved routine diagnosis for GIST.

The natural history of gastrointestinal subepithelial tumors arising from muscularis propria: an endoscopic ultrasound survey

AIM

The majority of lesions originating from muscularis propria of stomach, duodenum, and colon are gastrointestinal stromal tumors (GISTs). Surgery is indicated when endosonographic criteria of malignancy are met, but little is known about the natural history of lesions with benign endosonographic features. Aim of this study was to evaluate the natural course of benign-appearing lesions originating from muscularis propria in organs where GISTs significantly overcome leiomyomas.

MATERIALS AND METHODS

A total of 49 asymptomatic patients with hypoechoic lesions originating from the fourth layer of the gastrointestinal tract entered a follow-up program by means of endoscopic ultrasonography. All lesions were nonulcerated, <3 cm in maximal diameter, with regular margins, and cystic spaces of <3 mm.

RESULTS

After a mean follow-up of 31+/-20.8 months and a median of 2 (range, 1 to 5) endosonographies/patient, no change in echostructure or dimensions was seen in 44 subjects whereas in 5, an increase of at least 25% in 1 diameter occurred. Surgical removal was proposed to all: 1 patient refused (she is still alive and symptom-free after 4 y), 3 of the 4 lesions removed proved to be GISTs with very low or low risk of malignancy and 1 lesion was classified as a glomus tumor with no malignant appearance.

CONCLUSIONS

Even small and benign-appearing lesions from muscularis propria may increase in size over time but this increase cannot be considered as an index of malignancy. As most of these lesions are GISTs, a policy of surveillance is advisable.

Predicting malignant potential of gastrointestinal stromal tumors using endoscopic ultrasound

BACKGROUND

The aim of this study was to determine which EUS characteristics correlate with malignant potential of GISTs.

METHODS

All patients with a diagnosis of GIST based on surgical resection and preoperative EUS at our institution from January 2000 to July 2006 were identified. Pathology reports were used to determine NIH classification of each GIST and EUS exams were reviewed. EUS features were compared to NIH classification of very low/low risk malignant potential or intermediate/high risk malignant potential.

RESULTS

Fourteen patients had lesions of very low or low risk malignant potential, and 12 patients had lesions of intermediate or high-risk malignant potential. EUS features of tumor size (P = 0.002), irregular extraluminal border (P = 0.005), local invasion (P = 0.02), and heterogeneity (P = 0.02) were statistically significant correlates of intermediate or high risk malignant potential.

CONCLUSIONS

EUS characteristics of tumor size, extraluminal border, depth, and heterogeneity can be used to predict malignant potential of GISTs.

A guide for the diagnosis and management of gastrointestinal stromal cell tumors

Gastrointestinal stromal cell tumors (GISTs) are the most common mesenchymal neoplasm of the gastrointestinal tract and are frequently detected on routine endoscopy. Although only approximately 10-30% of GISTs are clinically malignant, all may have some degree of malignant potential. Preoperative determination of malignancy risk can be estimated from tumor size and location, but reliable histopathologic criteria are not currently available. Given such biological uncertainty, accurate diagnosis is essential to differentiate these lesions from other truly benign, subepithelial tumors. Endoscopic ultrasound-guided fine-needle aspiration has emerged as an important procedure to secure a tissue diagnosis of a GIST. When encountering GISTs, gastroenterologists are faced with challenging management decisions, especially in the face of small, incidentally discovered lesions. The majority of localized GISTs are managed via surgical resection, although a select few may be observed using serial endoscopic ultrasound examinations. This Review provides a general overview of GISTs, with an emphasis on their endoscopic diagnosis, the management of localized disease, and the management of incidentally discovered GISTs.

Diagnosis and management of GI stromal tumors by EUS-FNA: a survey of opinions and practices of endosonographers

BACKGROUND

There is no consensus regarding the best management strategy for diagnosing and treating GI stromal tumors (GISTs).

OBJECTIVE

Our purpose was to examine the practice patterns of endosonographers in diagnosing and managing GISTs, particularly features of GISTs suggestive of malignancy, features that prompt surgical referral, and surveillance patterns.

DESIGN

An invitation to complete an online survey was e-mailed to all 413 members of the American Society for Gastrointestinal Endoscopy EUS Special Interest Group.

RESULTS

A total of 134 (32%) members responded; 59% of respondents use EUS features combined with FNA findings to diagnose GIST, and 89% consider a c-kit-positive stain on FNA most suggestive of GIST. However, 60% would diagnose GIST when cytologic samples are insufficient for diagnosis, and 40% would diagnose GIST if cytologic samples are sufficient but c-kit is negative. A total of 92% use size as the main criterion to distinguish benign from malignant GISTs, and 90% refer lesions >5 cm for surgery. For lesions not resected, 70% survey annually, 19% less than annually, 10% more than annually, and 1% do not survey.

LIMITATIONS

The opinions of the respondents do not necessarily reflect the opinions and practices of endosonographers nationwide. There are inherent limitations to an online multiple-choice survey, including low response rates.

CONCLUSIONS

There are substantial practice variations in diagnosing, resecting, and surveying GISTs. A majority of our survey respondents have made the diagnosis of GIST without FNA confirmation. Size >5 cm is the feature used most to predict malignancy and to prompt surgical referral. Surveillance practices for unresected GISTs are variable. Evidence is needed to establish practice guidelines in this area.

Gastrointestinal stromal tumors (GISTs): a review

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasms in the gastrointestinal tract, which, over the last 10 years, have emerged from a poorly understood neoplasm to a well-defined tumor entity exhibiting particular molecular abnormalities and for which promising novel treatment modalities have been developed. GISTs probably arise from the precursor cell of the interstitial cell of Cajal, express KIT tyrosine kinase in most of the cases and harbor mutations of importance for individualized treatment. The molecular targets for therapeutic interventions are not only of importance for the treatment of GIST patients but also useful for in the development of novel drug modalities and new strategies in basic cancer therapy.

Comparative validation of c-kit exon 11 mutation analysis on cytology samples and corresponding surgical resections of gastrointestinal stromal tumours

OBJECTIVE

Studies have shown that c-kit mutation analysis of gastrointestinal stromal tumours (GISTs) obtained by endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) can be routinely performed. We validated c-kit exon 11 mutational analysis on cell block material obtained from fine needle aspiration cytology (FNAC) for diagnostic purposes and compared it with the same analysis in formalin-fixed paraffin-embedded full sections of the corresponding resection specimens.

METHODS

c-kit mutation analysis was done on cell block material obtained from ten cases encountered in our department from 1999 to 2008 on which FNAC was attempted pre-operatively. The findings were compared with analysis on full paraffin section of the corresponding resected tumours in seven cases where patients opted for resection. c-kit exon 11 was examined via bidirectional nucleic acid sequencing.

RESULTS

Our results showed 100% concordance for the presence and type of exon 11 mutation in the resected and aspirated tumours in all seven cases. These mutations had diagnostic value when compared with other neoplasms that are part of the cytomorphological differential diagnosis, such as leiomyosarcoma or gastric adenocarcinomas.

CONCLUSION

Molecular cytopathology is a powerful tool that can complement morphology and immunohistochemical assessment of cytological material in routine practice for the diagnosis and prognostication of GISTs. We briefly discuss the advantages and limitations of the fine needle method of obtaining tissue for the diagnosis and prognostication of GISTs, and its current therapeutic strategies.

Minimally invasive resection of gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GISTs) are rare neoplasms. The advent of electron microscopy and immunohistochemistry has led to the realization that these tumors originate from a pleuropotential cell known as the interstitial cell of Cajal (ICC). The morphologic features demonstrated as most predictive of recurrence or metastases are tumor size and mitotic rate. There is oncologic justification for minimally invasive resection techniques with gross margins for GISTs. Minimally invasive resection provides advantages to patients in terms of morbidity and recovery. A variety of endoscopic, laparoscopic, and hybrid techniques are described for surgically excising GISTs in different anatomic locations.

A systematic review on the clinical diagnosis of gastrointestinal stromal tumors

BACKGROUND

The aim of this work was to assess the prevalence of symptoms of gastrointestinal stromal tumors (GISTs) and the diagnostic yield of clinical procedures for its diagnosis.

METHODS

Medical databases were consulted between 1998 and 2006 for potentially relevant publications. All studies dealing with the clinical presentation of GIST and related diagnostic procedures were included. Two researchers worked independently on the study selection, quality assessment, data extraction, and analysis phases of the study.

RESULTS

Forty-six observational studies were included with a total of 4,534 patients. Gastrointestinal bleeding was the most common clinical presentation. Twenty studies provided adequate information on the diagnostic yield of various procedures. The pooled diagnostic yield of endoscopy + mucosal biopsy and of intestinal contrast radiography was 33.8% (0-100%) and 35.1% (11-100%), respectively, while that of EUS and that of EUS-FNA was 68.7% (40-100%) and 84.0% (73.8-100%), respectively. Abdominal CT scan and MRI had similar pooled diagnostic yields: 73.6% (34.8-100%), and 91.7% (75-100%), respectively.

CONCLUSION

Endoscopy + mucosal biopsy should be reserved to patients with gastrointestinal bleeding. EUS-FNA provides direct visualization of the neoplasm and adequate samples for molecular diagnosis. EUS, abdominal CT and MRI may be considered valid alternatives whenever EUS-FNA is unavailable or a cytological diagnosis is unnecessary.

Subepithelial mass lesions in the upper gastrointestinal tract

The finding of a mass lesion in the upper gastrointestinal tract at endoscopy with apparent normal overlying mucosa is common. The differential diagnosis of such lesions is broad and includes those of intramural or extramural origin. Endoscopic ultrasound provides accurate imaging of subepithelial mass lesions and characterizes them according to size, echogenicity, and origin including the histologic layer if the lesion is intramural which narrows the differential diagnosis. Endoscopic ultrasound allows a guided tissue sample to be obtained for histologic confirmation which is especially important for hypoechoic lesions arising from the 3rd or 4th echogenic layers. The purpose of this article is to review the diagnosis of the more common subepithelial mass lesions with an emphasis on endoscopic ultrasound and the subsequent management or monitoring.

Prediction of aggressiveness of gastrointestinal stromal tumours based on immunostaining with bcl-2, Ki-67 and p53

OBJECTIVE

While the use of fine needle aspiration (FNA) in the diagnosis of gastrointestinal stromal tumours (GISTs) is well-established, it can be difficult to predict the prognosis of GIST based on morphology alone. The objective of the current study was to determine if expression of bcl-2, Ki-67 and p53 correlated with the outcome of GISTs based on cytological material.

METHODS

Cell-blocks from 14 GISTs diagnosed by FNA were retrieved. Immunostaining was performed with antibodies against bcl-2, Ki-67 and p53. All cytological diagnoses were confirmed by positive immunostaining with c-kit and/or subsequent histological evaluation. Positivity for bcl-2, Ki-67 and p53 was defined as the presence of > or =10% cytoplasmic staining, > or =5% nuclear staining and > or =5% nuclear staining respectively.

RESULTS

The 14 patients consisted of seven males and seven females with a mean age of 58 years. The average follow-up interval was 46 months. Six had a benign course and eight developed recurrences/metastases. Thirteen (93%) cases showed positive staining for bcl-2. Positive Ki-67 and p53 staining was noted in one (7%) and seven (50%) cases respectively. The difference in staining for p53 between aggressive and non-aggressive GISTs was statistically significant. No statistically significant difference was noted for bcl-2 staining or Ki-67 labelling index between the two groups.

CONCLUSIONS

According to our observations, p53 immunostaining may be useful in predicting the outcome of GIST diagnosed by FNA; Ki-67 and bcl-2 are not useful as prognostic markers for GIST in FNA specimens.

Endoscopic diagnosis of gastrointestinal stromal cell tumors

PURPOSE OF REVIEW

To outline the recommended course of action when a subepithelial lesion is encountered during upper endoscopy. It will focus on the endoscopic and endosonographic features common to gastrointestinal stromal tumors, and the optimal tests performed to confirm the diagnosis of a gastrointestinal stromal tumor.

RECENT FINDINGS

The major recent finding of a mutation in the protooncogene c-kit which is unique to gastrointestinal stromal tumors has led to their reclassification as separate from other spindle cell tumors. Endoscopic ultrasound is a key component of the evaluation of submucosal lesions of the gastrointestinal tract, allowing determination of the wall layer of origin of the lesion and diagnostic sampling. Endosonographic features of gastrointestinal stromal tumors associated with high-risk lesions include size larger than 4-5 cm, irregular or invasive border, cystic spaces and malignant appearing lymph nodes. Endoscopic ultrasound-guided fine needle aspiration is generally adequate for tissue acquisition. Immunohistochemical analysis is performed on the tissue to differentiate gastrointestinal stromal tumors from other spindle cell neoplasms.

SUMMARY

The clinical behavior of gastrointestinal stromal tumors is variable. Accurate preoperative endoscopic characterization of the lesion with fine needle aspiration is critical for treatment decisions and for an assessment of prognosis.

[Gastrointestinal stromal tumors (GIST) of the stomach as a cause of upper gastrointestinal bleeding]

Gastrointestinal stromal tumors (GIST) is the most common mesenchymal tumor of the gastrointestinal tract. GIST is currently defined as a gastrointestinal tract mesenchymal tumor containing spindle cells (less commonly epitheloid cells or rarely both) and showing CD 117 (c-kit protein) positivity in more than 95% of cases. Although they may arise throughout the gut, the commonest site are stomach (60-70%), small intestine (20-30%), colorectum (5%) and esophagus (up to 5%). Rarely, GISTs develop in the retroperitoneum, omentum or mesentery. GIST originates from the intestinal cell of Cajal (ICC). ICCs are located in and around the myenteric plexus and are thought to function as intestinal pacemaker cells. Historicaly, GIST were often misclassified as leiomyomas or leiomyosarcomas. Subsequently, it has been determined that GISTs have distinct ultrastructural features and immunophenotypical markers compared with smooth muscle and smooth muscle tumors. GIST predominantly occur in middle aged and older patients, with no significant difference in the sex incidence. Data from the recent population study suggest an incidence of about 10-22 cases per million persons per year. Clinical presentation of GIST varies widely, and depends on tumor size and location. GISTs that caused symptoms tended to be larger with an average size of 6cm versus 2cm for asymptomatic GISTs. Symptoms are most commonly related to mass effect or bleeding. GISTs can grow very large before producing symptoms. Commonest symptom of gastric GIST is manifest or occult bleeding. Abudant, life-threateting bleeding that require urgent surgery is rare. For patient with primary, localized, nonmetastatic GIST, complete surgical resection represents the only chance for cure. Lymhadenectomy is not necessary, because lymph node metastasis is very rare. The 5 year survival rate in patients with resected primary GISTs ranges from 48-65%. Conventional chemotherapy and radiation therapy is ineffective in the treatment of GIST. Imatinib mesilate (a tyrosine kinase inhibitor) was confirmed to be effective against metastatic or unresectable GISTs.

Current issues in gastrointestinal stromal tumors: incidence, molecular biology, and contemporary treatment of localized and advanced disease

PURPOSE OF REVIEW

Few areas in oncology have witnessed the major paradigm shift that has been noted in the understanding and management of gastrointestinal stromal tumors. This review highlights the progress made over the last 2 years.

RECENT FINDINGS

Population-based studies have provided insight into the true incidence of gastrointestinal stromal tumors. Improved understanding of the molecular biology has provided prognostic implications and may guide treatment in the future. More mature follow-up data from phase III trials have proven that the targeted tyrosine kinase inhibitor imatinib mesylate is a dramatically effective agent, but the duration of its benefits are finite, and drug resistance is an increasingly more common phenomenon. Adjuvant and neoadjuvant trials of imatinib are currently underway. A second targeted tyrosine kinase inhibitor, sunitinib malate, has been approved for the treatment of imatinib-resistant gastrointestinal stromal tumors after recent encouraging results. Finally, the success with imatinib and sunitinib has encouraged investigators to reevaluate the role of surgery in advanced gastrointestinal stromal tumors.

SUMMARY

The multidisciplinary management of gastrointestinal stromal tumors serves as a model of how new targeted molecular therapies can be combined with traditional treatment modalities to improve survival in advanced malignancies.

Esophageal leiomyosarcoma diagnosed by endoscopic ultrasound-guided fine-needle aspiration

Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) has proven itself to be a reliable method for the diagnosis of gastrointestinal stromal tumors and other gastrointestinal mesenchymal neoplasms. The diagnosis and distinction of these entities remain important, as these neoplasms have different prognoses and treatment options. We present a case of a 14.5-cm esophageal mass in a 67-yr-old woman sampled by EUS-FNA. Smears showed a cellular, spindle cell lesion with marked cytologic and nuclear pleomorphism. A cell block showed neoplastic cells reacting strongly with antibodies to smooth muscle antigens and not with antibodies to keratin, CD34 and CD117. Resection confirmed the diagnosis of esophageal leiomyosarcoma. To the best of our knowledge, this represents the first reported case of an esophageal leiomyosarcoma diagnosed by EUS-FNA. Clinical, imaging, and cytologic features as well as differential diagnosis are discussed.