The utility of fine-needle aspiration in the diagnosis of gastrointestinal stromal tumors: a cytomorphologic and immunohistochemical analysis with emphasis on malignant tumors

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.

Succinate dehydrogenase-deficient gastrointestinal stromal tumor of stomach diagnosed by endoscopic ultrasound-guided fine-needle biopsy: Report of a distinct subtype in cytology

Succinate dehydrogenase (SDH)-deficient gastrointestinal stromal tumors (GISTs) are characterized by the lack of mutations in KIT receptor tyrosine kinase complex and platelet derived growth factor receptor-alpha (PDGFRA) that are commonly found in the majority of GISTs. SDH-deficient GISTs comprise approximately 5%-10% of all GISTs. This subset may be associated with Carney Triad and Carney-Stratakis syndrome. SDH-deficient GISTs show unique demographic, radiologic, morphologic findings, clinical behavior, and treatment response. To our knowledge, the identification and characterization of this subset of GISTs have not yet been described in the cytopathology literature. By understanding the clinical as well as the other unique features of this tumor, in addition to the rapidly evolving identification of specific molecular alterations and targeted therapies, cytopathologists may play an important role in the diagnosis and work-up of these patients to allow clinicians to better manage and treat them. We present a young female with gastric SDH-deficient GIST diagnosed by fine-needle biopsy with supporting surgical pathology follow-up and molecular confirmation. This report suggests that the diagnosis of SDH-deficient GIST can be made on cytology in the appropriate clinical setting by using cytomorphologic features and demonstrating SDH loss by IHC on the cell block. In addition, molecular testing may be possible on the cytology cell block or supernatant to confirm the 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.

Intestinal GIST masquerading as an ovarian mass: Diagnosed on FNAC

The preoperative diagnosis of metastatic intestinal gastrointestinal stromal tumors (GIST) on cytology can be quite difficult at times. The present case characterizes the cytomorphological and immunocytochemical features of GIST, emphasizing the utility of fine-needle aspiration cytology (FNAC) in the evaluation of spindle cell tumors of gastrointestinal tract. An accurate and early diagnosis of GIST affects the treatment, primarily allowing the use of tyrosine kinase inhibitors in unresectable or metastatic cases. Presence of highly cellular fragments of spindle-to-oval cells with variable degree of pleomorphism, atypia, and necrosis supplemented by immunocytochemistry can render a cytological diagnosis of GIST in dilemmatic clinical situations. Our case highlights the diagnostic role of FNAC in the evaluation of a pelvic mass, which was clinicoradiologically misdiagnosed as ovarian carcinoma.

Endoscopic ultrasound-guided fine-needle aspiration skill acquisition of gastrointestinal submucosal tumor by trainee endoscopists: A pilot study

BACKGROUND AND OBJECTIVES

Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is an effective method for tissue diagnosis of gastrointestinal submucosal tumors (SMTs) that are difficult to diagnose by standard endoscopic biopsy. However, the learning curve, especially for gastrointestinal SMT, has not been sufficiently established. The aim of our study was to assess the skill acquisition and diagnostic accuracy of EUS-FNA for gastrointestinal SMT in trainee endoscopists in order to elucidate the optimal starting standards of EUS-FNA.

MATERIALS AND METHODS

We prospectively evaluated 51 EUS-FNA procedures for gastrointestinal SMT between May 2010 and March 2014. The procedure was performed by two trainee endoscopists and two expert endoscopists. We investigated the diagnostic yield of EUS-FNA and the factors associated with the accuracy between the trainee endoscopists and expert endoscopists.

RESULTS

The rate of adequate EUS-FNA materials for histological examination was 86.3%. Although infections occurred in two cases (3.9%), which were managed conservatively, no severe complications were identified. Comparing the trainee endoscopists with expert endoscopists, there was no significant difference in the rate of gaining adequate specimen (76.5% vs. 82.3%, P = 0.4626). However, the mean number of passes of the trainees tended to be more than that of the expert endoscopists (2.1 pass vs. 1.7 pass, P = 0.0511), and lesions located in the middle third of the stomach were the predictive factors for nondiagnostic tumors by the trainee endoscopists (P = 0.0075).

CONCLUSION

EUS-FNA for gastrointestinal SMT by trainee endoscopists can be safely performed under the supervision of EUS-FNA expert endoscopists.

Utility of DOG1 Immunomarker in Fine Needle Aspirates of Gastrointestinal Stromal Tumor

BACKGROUND

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor of the gastrointestinal tract. DOG1 is a sensitive and specific immunohistochemical marker for the diagnosis of GIST. To date, no study has reported the utility of DOG1 immunocytochemistry on aspirate smears.

METHODS

Aspirates with a cytological diagnosis of GIST were retrieved. DOG1 immunocytochemistry was performed on aspirates with adequate material.

RESULTS

23 cases were included (11 primary, 2 recurrent, 10 metastatic). Primary tumors were most frequently located in the stomach; most metastatic tumors were in the liver. Tumor cells were arranged in cohesive clusters with high cellularity. Cells were spindled, had a low N:C ratio, and a moderate amount of cytoplasm, which was elongated and tapering. Characteristic nuclear features included elongated nuclei with blunt or tapering ends, fine chromatin, mild anisonucleosis, and longitudinal grooves. The mitotic count was low, including in metastatic tumors. DOG1 immunopositivity was noted in 57% of the cases examined. Histopathology was available in 5 cases, all diagnosed as GIST.

CONCLUSION

Cytology is a sensitive investigative modality for the preoperative diagnosis and confirmation of metastasis of GISTs. In ambiguous cases, DOG1 immunocytochemistry can serve as a valuable adjunct. Cytologic assessment, however, cannot predict malignant potential of GISTs as even metastatic tumors display bland nuclear features.

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.

Gastrointestinal tumors of the colon and rectum

Gastrointestinal stromal tumors (GISTs) of the colon and rectum are the most common mesenchymal tumors of the gastrointestinal tract. GISTs of the colon and rectum constitute ~5% of all cases. Although colorectal GISTs can be small and found incidentally, the majority appear to be high risk and carry a significant likelihood of recurrent and metastatic disease. Surgery remains the mainstay of treatment for primary disease. There is now considerable interest in GISTs because they can be treated effectively with targeted molecular therapies, specifically tyrosine kinase inhibitors (TKIs), such as imatinib mesylate and sunitinib malate. GISTs are best treated by a multidisciplinary team comprised of the surgeon, medical oncologist, pathologist, and radiologist in the initial evaluation, management, and in continued follow-up. Increasing the number of resectable cases through pharmacologic debulking, optimizing the timing of surgery and organ preservation, reducing recurrence and surgical morbidity, prolonging survival, and possibly enhancing response to imatinib through surgical cytoreduction are all potential benefits of multidisciplinary management.

Gastrointestinal Stromal Tumors: Actin Expression, a New Prognostic Factor?

The aim of this study is to analyze the clinical outcome of gastrointestinal stromal tumors (GISTs) and to determine new prognostic factors. We perform a retrospective study of all the patients diagnosed with GIST in any location and operated on between 2000 and 2008 at our institution. We analyzed 35 patients, 16 males (45.7%) and 19 females (54.3%), with a mean age of 64 ± 13.8 years. The tumors were located in the stomach in 22 patients (62.9%), in the small bowel in 10 (28.6%), and the retroperitoneum in three (8.6%). Referring to gastric GIST, endoscopy revealed an ulceration in the mucosa in five cases, suggesting an epithelial neoplasm. In all these cases, pathology of the biopsy specimen was nonconclusive. Survival rate at 1 and 5 years was 94.3 and 88.6 per cent, respectively. Disease-free survival at 1 and 2 years was 91.4 and 88.6 per cent, respectively. Analyzing prognostic factors, a lower disease-free survival was observed among patients with constitutional syndrome at diagnosis ( P = 0.000), small bowel GIST ( P = 0.037), and tumors not expressing actin ( P = 0.015). A lower global survival was observed among men ( P = 0,036), patients with an abdominal mass ( P = 0.033) or with constitutional syndrome ( P = 0.007) at diagnosis and tumors at a retroperitoneal location ( P = 0.0002). Gastric GIST may be confused with epithelial neoplasms, modifying the surgery. In our patients, masculine gender, constitutional syndrome and abdominal mass at diagnosis, small bowel and retroperitoneal location, and actin negative tumors are bad prognostic factors.

Endoscopic ultrasonography-guided fine-needle aspiration for diagnosing upper gastrointestinal submucosal lesions: a prospective study of 50 cases

The objective was to assess EUS-FNA for diagnosing intramural upper GI tract lesions. The subjects were 50 patients (21M/29F) with upper GI submucosal lesions who underwent EUS-FNA at a referral center for GI system over a 12-month period. All cases were followed for 1 year after initial EUS-FNA. Cytologic diagnoses were categorized as benign, malignant, suspicious for malignancy, mesenchymal tumor, endocrine tumor, or nondiagnostic. All tumors were assessed for various cytomorphologic features. The accuracy of the initial FNA diagnoses was evaluated for each patient who also underwent subsequent histopathological examination of a core biopsy and/or surgical biopsy/resection material of the same lesion. According to the site of the lesions; while 84% of all esophageal lesions were diagnosed as mesenchymal; 67% of all gastric lesions were mesenchymal. The sole lesion was nonmesenchymal (benign cyst) in duodenum. The sensitivity, specificity, positive and negative predictive values, and accuracy of EUS-FNA for diagnosing submucosal mesenchymal tumors of the upper GI tract were 82.9, 73.3, 87.9, 64.7, and 80%, respectively. The corresponding values for nonmesenchymal lesions were 100, 85.7, 80, 100, and 90.9%. Our experience confirms that EUS-FNA is an extremely valuable tool for diagnosing submucosal lesions of the upper GI, and is particularly useful in cases where endoscopic forceps biopsy does not lead to diagnosis. Optimal results can be yielded by a close working relationship between the gastroenterologist and pathologist.

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.