Fine needle aspiration of gastrointestinal stromal 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.

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.

Cytological Findings of Gastrointestinal Stromal Tumor-Derived Bone Metastasis

OBJECTIVE

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

STUDY DESIGN

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

RESULTS

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

CONCLUSION

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

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.

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 stromal tumors: the role of the gastroenterologist in diagnosis and risk stratification

Gastrointestinal stromal tumors (GISTs) are mesenchymal tumors that are best classified as sarcomas with variable aggressiveness. They are typically treated with surgical resection and adjuvant tyrosine kinase inhibitors or, for advanced/metastatic GISTs, with tyrosine kinase inhibitors alone. Gastroenterologists are often the first to detect GISTs and are, therefore, tasked with diagnosis and facilitation of early intervention. Diagnostic tools including various imaging techniques such as endoscopic ultrasound (EUS) and EUS-assisted tissue sampling are critical for an accurate diagnosis. In the case of small tumors, EUS-assisted resection or ligation techniques to treat asymptomatic small tumors have been described. This paper reviews current evidence for the diagnosis and management of GISTs, with an emphasis on the role of the gastroenterologist.

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.

DOG1 antibody is a highly sensitive and specific marker for gastrointestinal stromal tumors in cytology cell blocks

Initial diagnosis of submucosal gastrointestinal stromal tumors (GISTs) is often made from material obtained by endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA). Although 95% of GISTs are positive for KIT by immunohistochemical analysis on surgical specimens, we have observed several cases of GIST that were negative for KIT on the cell block but subsequently positive on the surgical resection. DOG1 has been found to be a specific and sensitive marker for GISTs on surgical material. We compared KIT and DOG1 staining in 52 GIST cell blocks and in 44 cell blocks of other intra-abdominal spindle cell neoplasms. We found that DOG1 was the more sensitive marker, with positivity in all 52 GIST cell blocks. KIT was positive in 46 (88%) of the GIST cases, with sensitivity dependent on the FNA method. Both markers were highly specific: KIT was negative in all 44 non-GIST cases, whereas DOG1 showed weak positivity in only 1 leiomyosarcoma.

Extra luminal colonic gastrointestinal stromal tumor: a case report

Introduction

Gastrointestinal stromal tumors are the commonest mesenchymal tumors of the gastrointestinal tract, the stomach and small intestine are the favored sites of occurrence. They rarely occur in the colon, rectum and esophagus. GIST is neoplasm of mesenchymal origin originating from precursors of the interstitial cells of cajal. The symptoms of gastrointestinal stromal tumor depend on the site and size of the tumor, and may include abdominal pain, gastrointestinal bleeding or signs of obstruction; small tumors may, however, be asymptomatic. Majority of the patients with gastrointestinal stromal tumor have bloody stools and abdominal pain as the commonest manifestation. We describe a young female with extra luminal colonic gastrointestinal stromal tumor presenting as mass abdomen.

Case presentation

We describe 34-year-old female from north Indian state of Jammu and Kashmir who had presented with history of slowly increasing epigastric lump associated with abdominal discomfort of 4 months duration. She had no features of luminal obstruction. Her contrast enhanced computed tomography abdomen revealed a large extra-colonic mass in relation to transverse colon. The tumor was resected and histology was suggestive of gastrointestinal stromal tumor.

Conclusion

Extra luminal colonic gastrointestinal stromal tumors are very rare and can present as mass abdomen. Resection is the treatment of choice.

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.

Extra luminal colonic gastrointestinal stromal tumor: a case report

INTRODUCTION

Gastrointestinal stromal tumors are the commonest mesenchymal tumors of the gastrointestinal tract, the stomach and small intestine are the favored sites of occurrence. They rarely occur in the colon, rectum and esophagus. GIST is neoplasm of mesenchymal origin originating from precursors of the interstitial cells of cajal. The symptoms of gastrointestinal stromal tumor depend on the site and size of the tumor, and may include abdominal pain, gastrointestinal bleeding or signs of obstruction; small tumors may, however, be asymptomatic. Majority of the patients with gastrointestinal stromal tumor have bloody stools and abdominal pain as the commonest manifestation. We describe a young female with extra luminal colonic gastrointestinal stromal tumor presenting as mass abdomen.

CASE PRESENTATION

We describe 34-year-old female from north Indian state of Jammu and Kashmir who had presented with history of slowly increasing epigastric lump associated with abdominal discomfort of 4 months duration. She had no features of luminal obstruction. Her contrast enhanced computed tomography abdomen revealed a large extra-colonic mass in relation to transverse colon. The tumor was resected and histology was suggestive of gastrointestinal stromal tumor.

CONCLUSION

Extra luminal colonic gastrointestinal stromal tumors are very rare and can present as mass abdomen. Resection is the treatment of choice.

Gastrointestinal stromal tumor arising from anorectum: correlation of imprint cytology and radiologic imaging

The diagnosis of gastrointestinal stromal tumor (GIST) is generally established on histopathologic examination of surgical specimens. Gastrointestinal stromal tumor comprises a heterogenous group of neoplasms of the gastrointestinal tract previously referred to as leiomyomas, leiomyosarcomas, or schwannomas. Gastrointestinal stromal tumor arising from anorectum is a rare instance. We report a case of GIST for the correlation of imaging and cytologic features with immunocytochemical staining. A computed tomography and magnetic resonance imaging confirmed a 2-cm tumor growing into the rectal lumen. The central portion of the tumor showed T1-weighted imaging of low signal and suspected central necrosis by the T2-weighted imaging of high signal. Imprint cytology from excised tumors showed isolated or loosely aggregated spindle cells with scanty and fibrillary cytoplasmic processes, nuclear pleomorphism, fine granular chromatin, and irregular nuclear margins. Epithelioid tumor cells showed grooves with abundant cytoplasm and several round nucleoli. Both c-kit and CD34 antigen were positive with strong and diffuse stainability in smears as well as paraffin sections by immunoperoxidase staining. We suggest that the combined use of imaging diagnosis and cytology with immunocytochemical staining are useful initial diagnosis of GIST.

Prognostic factors affecting survival after surgical resection of gastrointestinal stromal tumours: a two-unit experience over 10 years

BACKGROUND

Gastrointestinal stromal tumours (GISTs) are the most common mesenchymal neoplasm of the gastrointestinal (GI) tract which has only been recently described based on their specific immunohistochemistry and the presence of particular KIT-related mutations which potentially make them targets for tyrosine kinase inhibition.

METHODS

Sixty-one patients (29 M; 32 F, median age 60 years; range: 23-86 years) between June 1994 and March 2005, were analyzed from two allied institutions. Patient, tumour, and treatment variables were analyzed to identify factors affecting survival.

RESULTS

Of the 61 patients, 55 (90%) underwent complete surgical resection of macroscopic disease. The 5-year overall survival (OS) rate in the 61 patients was 88% and the 5-year disease-free survival (DFS) in the 55 cases completely resected was 75%. Univariate analysis revealed that R0 resection was strongly associated with a better OSrate (p < 0.0001). Likewise, univariate analysis also showed high mitotic count of > 10 mitoses/per 50 HPF was a significant variable in worse prognosis for OS (<or= 10 mitoses/per 50 HPF 95% 5-year OS vs. > 10 mitoses/per 50 HPF 74% 5-year OS, respectively; p = 0.013). On subsequent multivariate analysis, only high mitotic count remained as a significant negative prognostic variable for OS (p = 0.029). Among patients resected for cure, there were 8 recurrences during follow-up. The mean time to recurrence was 21 +/- 10 months (range: 4-36 months). Univariate analysis revealed that mitotic count of > 10 mitoses per 50 high power fields, intratumoural necrosis, and pathological tumour size (> 10 cm in maximal diameter) significantly correlated with DFS (p = 0.006, 0.002 and 0.02, respectively), with tumour necrosis and high mitotic count remaining as independent predictive variables affecting prognosis on subsequent multivariate analysis.

CONCLUSION

Most GISTs are resectable with survival principally dependent upon mitotic count and completeness of resection. Future metabolic and genetic analyses will define the role of and resistance to induction or postoperative adjuvant targeted kinase inhibition therapy.

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

BACKGROUND

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasms of the tubular gut and mesentery. Fine-needle aspiration biopsy (FNAB) currently is a useful tool in the diagnosis of GIST because of various mutations of the KIT protooncogene that are recognized as characteristic of these tumors. Despite such advances, the malignant potential of GIST remains variable, and few studies have reported their findings in patients with malignant GIST. Therefore, in the current study, the authors have reported their experience with FNAB as a diagnostic tool in one of the largest series of malignant GISTs and have analyzed the cytomorphologic features of the tumors relative to their clinical behavior to determine which, if any, cytologic features are indicators of malignancy.

METHODS

All patients with histologically confirmed GIST who were diagnosed by image-guided FNAB and confirmed with positive CD117 staining from 1998 to 2003 were included in the study. All tumors were reviewed for various cytomorphologic features. For study purposes, the patients were divided into two groups: Group A included all patients with malignant tumors, defined as those with metastatic disease or recurrent disease after adequate surgery with or without chemotherapy; Group B included all other patients.

RESULTS

In total, 26 tumors from 23 patients (8 males and 15 females) with a mean age of 60.9 years were available for review. There were 14 primary tumors, 7 metastases (to the liver), and 5 recurrences. Twenty-one tumors were unequivocally malignant and were placed into Group A; the remaining 5 tumors were placed into Group B. The tumors in both groups were characterized by spindled or epithelioid cells with minimal nuclear atypia or pleomorphism and a moderate amount of cytoplasm. None of the cytologic features that were evaluated could distinguish reliably between benign tumors and malignant tumors, as expected. However, on cytologic examination, all tumors that demonstrated mitoses (n = 7 tumors) and/or pretreatment necrosis (n = 3 tumors) were identified as malignant.

CONCLUSIONS

FNAB remains a reliable method for the diagnosis of GIST. Immunohistochemical staining of cytologic material with CD117 has been reliable in establishing this diagnosis by FNAB, provided adequate tissue is procured. In the current study, the presence of necrosis or mitoses in cytologic specimens was correlated with a diagnosis of malignant GIST.

Endoscopic ultrasound-guided fine-needle aspiration cytology for diagnosis above and below the diaphragm

Endosonography ultrasound (EUS) is a minimally invasive technology using a high-frequency ultrasound transducer that is incorporated into the tip of a conventional endoscope. This technique permits high-resolution imaging of the gastrointestinal wall and structures in its vicinity, as well as real-time endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA). This is a review of the literature on EUS-guided FNA of the mediastinal and abdominal lymph nodes, the pancreas, intramural gastrointestinal masses, and other miscellaneous organs and body cavities. EUS-guided FNA is a recently developed procedure that has established itself as a safe, highly accurate, and clinically useful modality.

c-KIT mutation analysis for diagnosis of gastrointestinal stromal tumors in fine needle aspiration specimens

BACKGROUND

Gastrointestinal stromal tumors (GISTs) are a specific clinicopathologic entity characterized by activating mutations in the c-KIT gene. These mutations are associated with increased immunohistochemical staining for the c-KIT protein. Because many GISTs display a definitive response to the KIT inhibitor imatinib, accurate diagnosis of these neoplasms is of great clinical importance. GISTs are the most common mesenchymal neoplasms of the digestive tract and show lineage differentiation along the lines of the interstitial cells of Cajal. The cytomorphology of GISTs has been well described, but the cytologic features are not entirely specific and immunohistochemical staining is frequently used to confirm the diagnosis. However, KIT protein positivity established by immunohistochemistry (IHC) may be unreliable in some instances because of a small number of KIT-negative GISTs and immunohistochemical KIT positivity in some non-GIST spindle cell neoplasms of the gastrointestinal tract. Antigen retrieval may be the cause of this spurious positivity. Recently, the demonstration of KIT and PDGFRA mutations has been shown to be more reliable in establishing the diagnosis of GIST than IHC.

METHODS

High resolution amplicon melting analysis was performed in a series of eight gastrointestinal stromal tumors sampled by fine needle aspiration (FNA).

RESULTS

In five of eight cases, adequate material was obtained for mutational analysis. In four of these, mutations in the c-KIT gene were detected, and in the fifth case a mutation in the PDGFRA gene was detected.

CONCLUSIONS

It appears that high resolution amplicon melting analysis can be successfully performed on material obtained by FNA and will show either KIT for PDGFR mutations in the majority of GIST FNA specimens.

Submucosal lesions

Most of the submucosal lesions encountered on endoscopy are benign; however, the fact that some of them may be malignant considerably influences the attitude toward the whole group. This article reviews the current status of endosonography in the management of submucosal lesions and focuses on determining the risk of malignancy. The predictive value of various endoscopic ultrasonography (EUS) features and their combinations and the capabilities and limitations of EUS-guided fine needle biopsy are discussed. Other issues addressed include differentiation between extraluminal compressions and true submucosal lesions, EUS-assisted endoscopic removal of submucosal lesions, and the potential role of catheter-based endosonography in the setting of submucosal lesions. Problems related to the surveillance of patients with submucosal lesions who are not candidates for surgical treatment are outlined. An overview of the recent changes in the pathologic classification of gastrointestinal mesenchymal tumors and their impact on the role of EUS in the management of submucosal lesions is given.

Gastrointestinal tract cytology: advancing horizons

Tide and ebb of interest in gastrointestinal tract cytology has followed technical advances in this field over the last 60 years. Cytologic samples can be obtained using gastric lavage, abrasive balloons, mucosal brushing, and fine needle aspiration (under percutaneous image guidance, endoscope and endoscopic ultrasound guidance). These advances now allow simultaneous performance of brushing the abnormal mucosa, obtaining fine needle aspirates and excising mucosal biopsy samples for evaluation. Use of endoscopic ultrasound guided fine needle aspirates now help to obtain diagnosis of submucosal lesions, preoperative staging of gastrointestinal tract malignancies and help determine further management of patients. Such advances have brought pathologists to the forefront of the patient management team for the treatment of gastrointestinal tract lesions. This manuscript reviews the advantages and limitations of each cytology associated technique as well as reviews the salient diagnostic features, differential diagnosis and diagnostic pitfalls of gastrointestinal tract lesions. Finally, it suggests the modalities best suited to obtain diagnosis for various gastrointestinal tract lesions.

Epithelioid variant of gastrointestinal stromal tumor: Diagnosis by fine-needle aspiration

Epithelioid gastrointestinal stromal tumors (GISTs) may cause significant diagnostic confusion on fine-needle aspiration (FNA) with carcinomas, neuroendocrine tumors, and melanoma, particularly when metastatic. This study characterizes the cytologic features of nine cases of epithelioid GISTs that were obtained by computerized tomographic guidance in five, by endoscopic ultrasound in three, and from an excised liver tumor in one. Six cases presented as liver masses, one as a perisplenic mass, one as an abdominal mass, and one as a gastric mass. The aspirates revealed mainly single or small clusters of epithelioid cells with a moderate amount of granular to clear cytoplasm, small uniform nuclei with mild to marked nuclear envelope irregularities. Binucleation and intranuclear inclusions were frequent findings. Collagenous stroma was seen in most cases. In three cases, a neuroendocrine tumor was the initial diagnosis. Immunocytochemical staining for c-kit (CD117) was performed on cellblocks in six cases and was positive in five cases. On the subsequent surgical specimen, CD117 was positive in the c-kit-negative cytology case. The diagnosis of GIST should be considered in aspirates of the gastrointestinal tract, liver, mesentery, or abdominal wall mass lesions when epithelioid cells are the predominant cell type. Ancillary studies such as immunohistochemical stains are usually helpful in making a definitive diagnosis.

Glomus tumor of the stomach: cytologic diagnosis by endoscopic ultrasound-guided fine-needle aspiration

The glomus tumor is usually a benign solitary neoplasm that arises from modified smooth muscle cells of the glomus body, a type of neuromyoarterial receptor that plays a role in the regulation of arterial blood flow. We report a case of gastric glomus tumor diagnosed by endoscopic ultrasound-guided fine-needle aspiration. Smears exhibited groups of cohesive, uniform, small, round to polygonal cells with scant cytoplasm, indistinct cell borders, and round, hyperchromatic nuclei with homogeneous chromatin. The cell block contained fragments of cells with similar morphologic features and immunohistochemical staining exhibited positivity for smooth muscle actin and vimentin. The diagnosis was confirmed by the surgically resected specimen. Ultrastructural examination revealed prominent pinocytotic vesicles lining the plasmalemma. In this report, we discuss the differential diagnosis of gastric glomus tumor and compare the cytologic features of this case with two others reported in the literature.

A comparison of EUS features between CD-117 positive GI stromal tumors and CD-117 negative GI spindle cell tumors

BACKGROUND

GI stromal tumors are spindle cell tumors that stain positive for immunohistochemical CD-117 (c-kit). Prognostic factors for malignancy include size (> or =4 cm), mitotic index (5 mitotic figures/50 high-powered fields), and ulcerated, cystic, or necrotic areas within the tumor. The purpose of this study was to compare these features in c-kit positive vs. c-kit negative tumors.

METHODS

All patients referred for EUS of submucosal lesions were identified, and histopathology, including immunohistochemical staining, was reviewed to determine all diagnoses of GI stromal tumors. Size, echo pattern, and presence of cystic spaces and ulceration were recorded as diagnosed by EUS. Histopathologic diagnoses were made by FNA or endoscopic submucosal-mucosal resection. If surgical resection followed, the surgical diagnosis, staining pattern, mitotic index, and presence of ulceration, necrosis, and nuclear atypia were recorded.

RESULTS

Forty patients (21 men, 19 women; 38 white, 2 African American; mean age 58 +/- 2.6 years) had 46 EUS procedures performed for evaluation of spindle cell tumors. Seventeen stained positive for c-kit (mean age, 59 +/- 3.6 years; range 19 to 80 years) and 12 negative (mean age, 57 +/- 3.8 years; range 31 to 76 years); 11 were not stained for c-kit (excluded from analysis). On EUS, 7 were ulcerated, 3 cystic, and 6 were larger than 4 cm. This group of findings was observed in 12 patients, 11 of whom had c-kit positive tumors (11/17 vs. 1/12; p = 0.006). Tumors positive for c-kit were larger (42.4 +/- 5.5 mm vs. 19.0 +/- 5.9 mm; p = 0.005). There were 13 c-kit positive tumors in the stomach, 2 in the duodenum, and 1 each in the esophagus and at the gastroesophageal junction. Of the 12 c-kit negative tumors, 8 were located in the esophagus and 1 at the gastroesophageal junction (9/12 vs. 2/17; p < 0.01). Surgical resection was performed on 13 patients, 12 of whom had c-kit positive tumors, and 3 of these 12 tumors had greater than 5 mitoses per 50 high-powered field.

CONCLUSIONS

If a GI stromal tumor is suspected, EUS-FNA with immunohistochemical staining should be performed for CD-117 (c-kit). C-kit tumors are more likely to have malignant features and should be resected or subjected to close clinical follow-up.

Fine-needle aspiration cytology and immunocytochemistry in the diagnosis of 24 gastrointestinal stromal tumors: a quick, reliable diagnostic method

The diagnosis of gastrointestinal stromal tumors (GISTs) is generally established on histopathologic examination of surgical specimens. Fine-needle aspiration (FNA), performed under the guidance of ultrasound or computed tomography, is being used with increasing frequency in an attempt to diagnose primary and/or metastatic GISTs before surgery. The present study was undertaken to characterize the cytological appearance of these tumors and to assess the role of cytology, together with immunocytochemistry (ICC), in the diagnosis of GISTs. Twenty-four GISTs diagnosed by FNA cytology at our institution have been reviewed. Immunocytochemical studies with c-kit and CD34 were performed in all cases on current or archival Papanicolaou-stained smears. All cases stained with c-kit, and 19 reacted with CD34. Cytomorphology and immunocytochemical characteristics are discussed. Our results confirm the utility of FNA together with ICC in the diagnosis of primary and/or metastatic GISTs.

Fine-needle aspiration cytology diagnosis of metastatic gastrointestinal stromal tumor in the liver: a report of three cases

Gastrointestinal stromal tumor (GIST) is the designation for a major subset of gastrointestinal mesenchymal tumors that histologically, immunocytochemically, and genetically differ from leiomyomas, leiomyosarcomas, and schwannomas. GISTs derive from the interstitial cells of Cajal and, in addition to variable expression of smooth muscle and neural markers, they characteristically express CD34 and CD117. The cytological appearance, including immunocytochemical and mutational analysis of c-kit gene in primary GIST has been well described. To our knowledge, only two cases of metastatic GIST diagnosed by fine-needle aspiration (FNA) have been reported. We illustrate three cases of metastatic GIST in the liver. Two cases had no prior history of gastrointestinal tumor and the third case had a 4-yr previous history of duodenal tumor. Consistent immunocytochemistry and ultrastructual studies supported the diagnosis of GIST. We emphasize that in the appropriate clinical and radiological setting, a confident diagnosis of GIST can be established by FNA of metastatic lesions.

Epithelioid gastrointestinal stromal tumor of the stomach with liver metastases in a 12-year-old girl: aspiration cytology and molecular study

Gastrointestinal stromal tumor (GIST), a stromal tumor of the gastrointestinal tract defined as CD117 (c-kit)-positive neoplasm, occurs primarily in adults. GIST with CD117 (c-kit) mutation and certain cytogenetic abnormalities is associated with malignancy, though a definite relationship between prognosis and molecular alterations remains to be elucidated. We report the cytologic features of an epithelioid GIST arising in the stomach of a child and metastatic to the liver, and the molecular mutational analysis of both the primary gastric tumor and the liver metastasis. Literature of pediatric GISTs was also reviewed. Fine needle aspiration of the liver metastasis, processed by Ultrafast Papanicolaou stain, showed fragments of cohesive small epithelioid cells with bland oval nuclei and unipolar cytoplasm transected by capillaries. Immunohistochemically, all nodules in the stomach and liver expressed CD117 (c-kit). Interestingly, some of the gastric tumor clusters were uniformly CD34 positive, whereas others were uniformly CD34 negative, suggesting heterogeneity of tumor clones. The presence of neurosecretory granules further subtyped the tumor into gastric autonomic nerve tumor (GANT). Molecular mutational analysis, performed in both the gastric tumor and the liver metastasis, showed no sequence abnormality in exons 9, 11, and 13 of CD117 (c-kit). Cytogenetic study revealed normal karyotype. These features might suggest a different molecular mechanism leading to malignancy in certain GISTs arising in children.

Cytologic diagnosis of gastrointestinal stromal tumors of the stomach by endoscopic ultrasound-guided fine-needle aspiration biopsy: cytomorphologic and immunohistochemical study of 12 cases

Gastrointestinal stromal tumor (GIST) is an uncommon tumor, which was usually diagnosed by endoscopic biopsy or surgical resection. This study evaluated the efficacy and accuracy of endoscopic ultrasound (EUS) -guided fine-needle aspiration (FNA) biopsy in the diagnosis of GIST and reported its cytomorphologic features. Twelve patients with gastric GIST were diagnosed through EUS-guided FNA. Immediate on-site evaluation and cytologic diagnoses were given in nine cases (75.0%) with an average of three passes. Cell blocks provided diagnostic material in three cases (25.0%). Spindle cells were present in the cytologic material in all cases. Two patients had subsequent surgical resections. Immunohistochemical (IHC) studies performed in cell blocks and two surgical specimens all supported the original diagnoses. In the two cases with surgical resections, IHC results in cell blocks were similar to that in the resected specimens. This study demonstrated that when combining smears and cell blocks, EUS-guided FNA is accurate and efficient in the diagnosis of GIST. IHC reactivity in cell blocks correlated with that of the main tumors.

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

BACKGROUND

Differentiating gastrointestinal stromal tumors (GISTs) from other intramural mesenchymal tumors of the GI tract on fine-needle aspiration biopsies (FNABs) is difficult. Recent studies have shown that GISTs are immunophenotypically and genetically distinct. GISTs exhibit consistent immunohistochemical expression of CD-117 (KIT) and often express activating mutations of this protooncogene. The aim of the current study was to employ immunocytochemistry and mutational analysis of the c-kit gene to aid in the diagnosis of GISTs on FNAB.

METHODS

Five endoscopic ultrasound-guided FNABs of gastrointestinal spindle cell neoplasms performed at the Veterans Affairs Medical Center (VAMC) in Portland, Oregon, from 1998-1999 were reviewed. A panel of immunocytochemical stains was performed on each cellblock including CD-117 (KIT), smooth muscle actin (SMA), desmin, S-100, and CD34. Genomic DNA (gDNA) was extracted, and amplification of exons 9, 11, 13 and 17 of c-kit was performed by polymerase chain reaction (PCR) on CD-117 (KIT) and CD34 positive cases. Direct sequencing of amplicons identified the mutations.

RESULTS

Five patients were diagnosed with GISTs based on morphology and immunocytochemical positivity for CD-117 and CD34. PCR analysis of c-kit exon 11 revealed three cases with novel-sized PCR bands in addition to the expected wild-type-sized PCR product. Amplicons from these cases contained an in-frame deletion mutation. One of the two cases with wild-type-;sized exon 11 amplicons was found to be heterozygous for a point mutation producing an amino acid substitution (W557R). No mutations in exon 9, 11, 13, or 17 of c-kit were found in the remaining case.

CONCLUSIONS

Ancillary techniques such as immunocytochemistry and c-kit gene mutational analysis may aid in the diagnosis of GISTs on FNABs.

Cytologic diagnosis of gastrointestinal stromal tumor with emphasis on the differential diagnosis with leiomyosarcoma

BACKGROUND

Gastrointestinal stromal tumor (GIST) has only recently been distinguished histologically and immunochemically from morphologically similar neoplasms of the abdomen.

METHODS

The authors reviewed 15 cytologic cases of GIST (14 fine-needle aspiration [FNA] specimens and 1 peritoneal fluid specimen) and compared them with 23 cases of leiomyosarcoma (LMS) arising in the abdomen or pelvis (all FNAs). Immunochemistry (IC) was performed on both the cytologic and subsequent tissue specimens if sufficient specimen was available.

RESULTS

Cytologic samples of GISTs typically showed irregularly outlined clusters of uniform spindle cells that were spread easily without crush artifact. The cells had wispy cytoplasm with long, delicate, filamentous extensions (13 cases; 87%). A prominent vascular pattern was common (9 cases; 60%); pleomorphism (1 case; 7%) was uncommon. The LMSs showed three-dimensional, tightly cohesive, sharply marginated syncytia of spindle cells, often with nuclear crush artifact. The cytoplasm/stroma had a distinct wiry, refractile appearance (21 cases; 91%); delicate filamentous cytoplasmic extensions (5 cases; 22%) and prominent vessels (3 cases; 13%) were less common. LMSs more commonly exhibited pleomorphism (14 cases; 61%). Epithelioid cytomorphology, mitoses, and necrosis occasionally were observed in both tumor types. IC for c-kit (on cytologic material) was positive in 10 of 10 cases of GIST (usually diffuse and strong) and 2 of 19 cases of LMS (focal). CD34 positivity favored GIST (4 of 9 cases) over LMS (1 of 19 cases). Smooth muscle actin was positive in 20 of 20 LMSs (strong and diffuse) and 6 of 10 GISTs (usually focal). Desmin was positive in 12 of 20 LMSs and was only focally positive in 1 of 11 GISTs. Correlation of IC results was excellent between cytologic and tissue specimens.

CONCLUSIONS

Delicate cytoplasmic processes; a prominent vascular pattern; a lack of nuclear pleomorphism; and a c-kit-positive, desmin-negative immunoprofile are characteristic features of GIST and help distinguish these tumors from LMS in cytologic specimens.