Gastrointestinal stromal tumor of the stomach: How to manage?

Common Symptoms and a Rare Diagnosis: A Case of Duodenal Gastrointestinal Stromal Tumor Presenting as Gastrointestinal Bleeding

Duodenal gastrointestinal stromal tumors (D-GISTs) are a rare subtype of GISTs, accounting for only 4% to 5% of all GIST cases. This case report details the presentation, diagnosis, and management of a 48-year-old female who presented with melena and anemia and was eventually diagnosed with a D-GIST. The tumor was identified through imaging studies, and histopathology performed after surgical resection revealed a submucosal neoplasm composed of spindle cells with extensive hemorrhage and necrosis. Given the tumor's rarity and its challenging presentation, which can mimic other conditions such as pancreatic masses, the case underscores the importance of considering D-GIST in differential diagnoses of duodenal or pancreatic lesions. Surgical resection remains the cornerstone of treatment, with adjuvant therapy considered in high-risk cases to prevent recurrence.

Comparing gastrointestinal stromal tumor outcomes between geriatric and non-geriatric patients: A population-based analysis

BACKGROUND

Gastrointestinal Stromal Tumors (GISTs) are the most common mesenchymal tumors of the GI tract. SEER is an extensive cancer database which proves useful in analyzing population trends. This analysis investigated GIST outcomes between geriatric & non-geriatric patients.

METHODS

SEER*STAT 8.4.0.1 was used to extract relevant GIST data from 2000 to 2019. Geriatric age was defined as ≥70 years. Variables included age, sex, surgery, cancer-specific death, and overall survival. Statistical tests included univariate analysis using KM survival estimate (95% confidence interval) to calculate 5-year survival (5YS). Log-Rank tests determined statistical significance. Multivariable Cox's PH regression estimated the geriatric hazard death ratio adjusted for sex, stage, and surgery.

RESULTS

The number of patients included was 13,579, yielding overall 5YS of 68.6% (95% CI 67.7-69.5). Cancer-specific death was 39.11% in 2000 & 3.33% in 2019. Non-geriatric & geriatric patient data yielded 5YS of 77.4% (76.4%-78.3%) and 53.3% (51.7%-54.8%) respectively (p < 0.0001). For no surgery/surgery, younger patient data yielded 5YS of 48.7% (45.8%-51.4%) and 83.7% (82.7%-84.7%) respectively (p < 0.0001); geriatric data yielded 5YS of 29.3% (26.5%-32.1%) and 62.8% (60.8%-64.6%) respectively (p < 0.0001). Multivariable analysis yielded a geriatric hazard death of 2.56 (2.42-2.70) (p < 0.0001).

CONCLUSIONS

Cancer-specific death decreased since 2000, indicating an improvement in survival & treatment methods. Observed lower survival rates overall in the geriatric group. Surgery appeared to enhance survival rates in both groups, suggesting that surgery is an important factor in GIST survival regardless of age. Large prospective studies will help define clinical management for geriatric patients.

Efficacy and histologic frequencies of endoscopic ultrasonography-guided tissue acquisition using conventional fine-needle aspiration needles for gastric subepithelial hypoechoic mass

Introduction/Purpose

For gastric subepithelial lesions (GSELs) showing a hypoechoic mass (HM) on endoscopic ultrasonography (EUS) imaging, the utility of EUS-guided tissue acquisition using conventional fine-needle aspiration needles (EUS-TA-CFNAN) and the frequency of histological types remain unclear. This study aimed to examine this issue.

Methods

This prospective observational study enrolled 291 consecutive patients who underwent EUS-TA-CFNAN for GSELs showing an HM (GSELHM) on EUS imaging. Immunohistochemical analysis was performed for all EUS-TA-CFNAN and surgically resected specimens. The main outcome measures were the technical results of EUS-TA-CFNAN and the frequency of histological types in GSELHM.

Results

The endoscopic ultrasound-guided tissue acquisition using conventional fine-needle aspiration needle diagnosis rate for GSELHM was 80.1% (95% confidence interval [CI]: 75.0-84.5, 233/291). It was significantly lower for antrum (P = 0.004) and lesions smaller than 2 cm (P = 0.003). There were no adverse events. The immunohistochemical diagnoses of EUS-TA-CFNAN included 149 cases of gastrointestinal stromal tumour (GIST) (51.2%), 48 cases of leiomyoma (16.5%), 11 cases of schwannoma (3.8%), 8 cases of the ectopic pancreas (2.7%), 5 cases of subepithelial lesion like cancer (1.7%), 12 cases of other lesions (4.1%), and 58 cases of undiagnosable lesions (19.9%). The frequency of malignant or potentially malignant tumour in GSELHM was 55.0% (95% CI: 49.1-60.8, 160/291). Surgery was performed in 149 patients according to the conclusive EUS-TA-CFNAN results, in which the diagnostic accuracy of EUS-TA-CFNAN was 97.3% (95% CI: 94.7-99.9, 145/149).

Conclusion

The use of EUS-TA-CFNAN for GSELHMs is safe and accurate. Gastric subepithelial lesions showing a hypoechoic mass have a reasonably high possibility of containing malignant or potentially malignant tumours, including GISTs.

Hallmarks and novel insights for gastrointestinal stromal tumors: A bibliometric analysis

BACKGROUND

Due to the increasing recognition of gastrointestinal stromal tumor (GIST), novel insights have appeared in both preclinical and clinical research and begun to reshape the field. This study aims to map the research landscape through bibliometric analysis and provide a brief overview for the future of the GIST field.

METHODS

We searched the Web of Science Core Collection without publication data restrictions for GISTs and performed a bibliometric analysis with CiteSpace and VOSviewer software.

RESULTS

In sum, 5,911 of 13,776 records were included, and these studies were published in 948 journals and written by 24,965 authors from 4,633 institutions in 100 countries. Referring to published reviews and bibliometric analysis, we classified the future trends in four groups. In epidemiological study, precise incidence and clinicopathological features in different regions and races might become potential hotspots. Novel therapy, such as drugs, modified strategies, radioligand therapy, was persistent hotspots in GIST fields, and ctDNA-guided diagnosis, monitoring, and treatment might meet future clinical needs. The debate over serosa surgery vs. mucosa surgery will remain active for a long time in GIST surgery, and function reserve surgery, biology-based surgery will play an important role in future. Moreover, rare GIST type, like NF-1-associated GIST, Carney triads and SDH mutant GIST, need more studies in pathogenesis and genetic mutation to provide appropriate treatment for this orphan GIST patients.

CONCLUSIONS

Potential hotspots in future GIST trends might involve epidemiology, agents, resection therapy and rare type GIST, moreover, researchers could pay more attention in these four fields.

Endoscopic Ultrasonography-Guided Fine-Needle Aspiration for Duodenal Subepithelial Lesions Showing a Hypoechoic Mass on Endoscopic Ultrasound Imaging

BACKGROUND/AIMS

For duodenal subepithelial lesions showing a hypoechoic mass on endoscopic ultrasound imaging, the utility of endoscopic ultrasound-guided fine-needle aspiration and the frequency of histological types have not been the focus of previous literature. This study aimed to clarify this.

MATERIALS AND METHODS

This prospective observational study enrolled 22 consecutive patients who underwent endoscopic ultrasoundguided fine-needle aspiration for duodenal subepithelial lesions with hypoechoic mass on endoscopic ultrasound. Immunohistochemical analysis was performed for all endoscopic ultrasound-guided fine-needle aspiration and surgically resected specimens. The main outcome measures were the technical results of endoscopic ultrasound-guided fine-needle aspiration and the frequency of histological types of duodenal subepithelial lesions with hypoechoic mass.

RESULTS

Thirteen fine-needle aspiration specimens were obtained from the duodenal bulb and eight from the descending duodenal region. The puncture was not performed because of intervening vessels in one patient. The diagnostic rate was 81% (95% confidence interval: 58.1-94.6, 17/21 patients). In 12 patients receiving surgical resection (excluding one cancellation of endoscopic ultrasoundguided fine-needle aspiration), the diagnostic accuracy of endoscopic ultrasound-guided fine-needle aspiration was 75% (95% confidence interval: 42.8-94.5, 9/12 patients). No complications were observed. The histopathological diagnoses included 11 cases of gastrointestinal stromal tumor (50%), 2 cases of leiomyoma (9%), 2 cases of metastatic cancer (9%), 2 cases of benign inconclusive, and 1 case each of carcinoid, malignant lymphoma, leiomyosarcoma, gauzeoma, and aberrant pancreas (4.5% each). The frequency of malignant tumors in the duodenal subepithelial lesions with hypoechoic mass group was 73% (16/22 patients).

CONCLUSIONS

Endoscopic ultrasound-guided fine-needle aspiration for duodenal subepithelial lesions with hypoechoic mass was safe and accurate. As duodenal subepithelial lesion with hypoechoic mass has a reasonably high possibility of containing malignant tumors, it is desirable to perform endoscopic ultrasound-guided fine-needle aspiration.

A national cancer database analysis of the clinicopathologic characteristics and outcomes of appendiceal malignant mesenchymal tumors

The present study aimed to assess the characteristics and outcomes of appendiceal malignant mesenchymal tumors. This was a retrospective case-series study of patients with appendiceal malignant mesenchymal tumors in the national cancer database (2005-2019). The main outcomes were overall survival (OS) and short-term mortality. 53 patients (40 GISTs and 13 sarcomas) were included. 92.6% of GIST patients had stage I disease and 76.9% of GISTs were ≤2 cm. Most appendiceal GISTs were treated with appendectomy or partial colectomy whereas half of patients with appendiceal sarcoma underwent hemicolectomy or subtotal colectomy. Only one short-term mortality was recorded in the sarcoma group. One-third of patients with sarcoma had positive surgical margins versus 5.1% of patients with GISTs. GIST patients had longer median OS (117.1 vs 54.8 months) than sarcoma patients.

Transarterial Embolization and Percutaneous Ablation of Primary and Metastatic Soft Tissue Tumors

Soft tissue tumors (STTs) include a range of benign and malignant tumors originating from soft tissues. Transarterial and percutaneous therapies are image-guided and minimally invasive approaches for managing primary and metastatic STTs. The objective of this review is to discuss transarterial and percutaneous therapies by examining the current literature, including indications, patient selection, safety, and effectiveness. Transarterial therapies (e.g., transarterial bland embolization and transarterial chemoembolization) involve the delivery of either embolic or chemotherapeutic particles using a catheter into arteries feeding the tumor, resulting in localized tumor destruction. Percutaneous therapies (e.g., radiofrequency ablation, cryoablation, irreversible electroporation, laser ablation, and magnetic resonance-guided high-intensity focused ultrasound) involve the delivery of either hot or cold temperatures, electrical current, laser, or ultrasound to specifically target tumor cells. Both therapies have been shown to be safe and effective for reducing morbidity and local control of STTs, specifically in patients who are surgically inoperable or who are unresponsive to conventional therapies. Accurate diagnosis, staging, and histological subtype identification are crucial for treatment selection. A multidisciplinary approach, a thorough understanding of tissue anatomy and surrounding structures, as well as individualized strategies based on assessment are essential for optimal patient care.

Endoscopic Ultrasound Advanced Techniques for Diagnosis of Gastrointestinal Stromal Tumours

Gastrointestinal Stromal Tumors (GISTs) are subepithelial lesions (SELs) that commonly develop in the gastrointestinal tract. GISTs, unlike other SELs, can exhibit malignant behavior, so differential diagnosis is critical to the decision-making process. Endoscopic ultrasound (EUS) is considered the most accurate imaging method for diagnosing and differentiating SELs in the gastrointestinal tract by assessing the lesions precisely and evaluating their malignant risk. Due to their overlapping imaging characteristics, endosonographers may have difficulty distinguishing GISTs from other SELs using conventional EUS alone, and the collection of tissue samples from these lesions may be technically challenging. Even though it appears to be less effective in the case of smaller lesions, histology is now the gold standard for achieving a final diagnosis and avoiding unnecessary and invasive treatment for benign SELs. The use of enhanced EUS modalities and elastography has improved the diagnostic ability of EUS. Furthermore, recent advancements in artificial intelligence systems that use EUS images have allowed them to distinguish GISTs from other SELs, thereby improving their diagnostic accuracy.

Incidentally Detected Gastrointestinal Stromal Tumor in a Patient with Carcinoma Prostate: 68Ga-Prostate-Specific Membrane Antigen Versus 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography

Uptake of 68Ga-prostate-specific membrane antigen (PSMA) in various nonprostatic tumors is well documented in the literature. We present a case of a gastrointestinal stromal tumor, incidentally detected on 68Ga-PSMA positron emission tomography/computed tomography imaging in a patient who underwent imaging for a suspected recurrence of carcinoma prostate.

Prediction of Gastric Gastrointestinal Stromal Tumors before Operation: A Retrospective Analysis of Gastric Subepithelial Tumors

Gastrointestinal stromal tumors (GISTs), leiomyomas, and schwannomas are the most common gastric subepithelial tumors (GSETs) with similar endoscopic findings. Preoperative prediction of GSETs is difficult. This study analyzed and predicted GSET diagnosis through a retrospective review of 395 patients who underwent surgical resection of GISTs, leiomyomas, and schwannomas measuring 2–10 cm. GSETs were divided by size (group 2–5, >2 and ≤5 cm; group 5–10, >5 and ≤10 cm) for analysis. Demographics, clinical symptoms, and images were analyzed. A recursive partitioning analysis (RPA) was used to identify optimal classifications for specific GSET diagnoses. GIST patients were relatively older than other patients. Both groups had higher proportions of UGI bleeding, lower hemoglobin (Hb) levels, and a higher ratio of necrosis on their computed tomography (CT) scans. The RPA tree showed that (a) age ≤ 55, Hb ≥ 10.7, and CT necrosis; (b) age ≤ 55 and Hb < 10.7; (c) age >55 and Hb < 12.9; and (d) age >55 and CT hetero-/homogeneity can predict high GIST risk in group 2–5. Positive or negative CT necrosis, with age >55, can predict high GIST risk in group 5–10. GIST patients were older and presented with low Hb levels and tumor necrosis. In RPA, the accuracy reached 85% and 89% in groups 2–5 and 5–10, respectively.

Gastric carcinoma with lymphoid stroma diagnosed by endoscopic ultrasound-guided fine-needle aspiration

A 78-year-old man with a subepithelial lesion (SEL) in the gastric body and two carcinomas in the gastric antrum was referred to our hospital. Following a diagnosis of SEL, the patient was followed-up by esophagogastroduodenoscopy annually for 4 years. Although the SEL had increased in size over the years, histological evaluation of the forceps biopsies did not reveal any significant findings. We detected a hypoechoic mass in the submucosa by endoscopic ultrasonography, and suspected the lesion to be an aberrant pancreas or mesenchymal tumor. The patient first underwent endoscopic submucosal dissection for the 2 gastric cancers. Histological examination of the resected specimens revealed intramucosal well-differentiated tubular adenocarcinomas. Next, endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) was performed for the gastric SEL. Aspirated specimens revealed an adenocarcinoma with lymphocyte infiltration. The lesion was diagnosed as a gastric carcinoma with lymphoid stroma (GCLS). Subsequently, he underwent distal gastrectomy, and the surgical specimen was confirmed as GCLS corresponding to preoperative diagnosis. In addition, the adenocarcinoma cells were positive for Epstein-Barr (EB) virus-encoded small RNA-1 by in situ hybridization. Finally, the lesion was diagnosed as GCLS associated with EB virus. Thus, EUS-FNA is advantageous for diagnosing GCLS associated with EB virus.

Gastrointestinal Stromal Tumor (GIST) Causing Obscure Gastrointestinal Bleeding: An Uncommon Way of Diagnosing An Uncommon Disease

Gastrointestinal stromal tumors (GISTs) are neoplasms that arise from the wall of the gastrointestinal tract or, rarely, from other intra-abdominal tissues. They are the most common mesenchymal tumors of the gastrointestinal tract and they should be considered in the differential diagnosis of obscure gastrointestinal bleeding. Computed tomography angiogram (CTA) can be utilized as an alternative imaging study when endoscopic and colonoscopy results are non-diagnostic. We report a case of a 59-year-old woman who presented with recurrent episodes of obscure overt gastrointestinal bleeding secondary to a gastrointestinal stromal tumor (GIST).

Characteristic of extra luminal gastric stromal tumor arising from the lesser curvature of the stomach: A case report

RATIONALE

Gastrointestinal stromal tumor (GIST) is one of the most common malignant mesenchymal tumors of the gastrointestinal tract. They generally arise from the fourth layer (muscularis propria) and rarely from the second or third layer. Although the manifestations of gastric stromal tumors are diverse, to our knowledge, there are only several cases of an extra-gastric stromal tumor in the literature appearing with a pedunculation. Pedunculated large GISTs are not frequent and compress the neighboring organs. When they were huge, it is difficult to differentiate the origin of the masses. Thus, in the clinical setting, physicians should pay more attention to the pattern of manifestation of the gastric stromal tumor.

PATIENT CONCERNS

A 62-year-old man had no gastrointestinal symptoms or significant medical and family histories. During the health examination with US, a cystic-solid tumor was found below liver. The results of the physical examination were unremarkable, and routine laboratory data on admission did not show any abnormal findings.

DIAGNOSIS

Computed tomography of the abdomen showed a mixed echoic mass measuring 10 × 8 × 8 cm and located below the liver, adjacent to the gastric antrum. After endoscopic ultrasound-guided fine-needle aspiration, cytopathology showed that the specimen was filled with red blood cells, and it had no malignant cells. Histopathology revealed that the mass was a GIST, and immunohistochemical analysis showed the following: CD117(+), CD34(+), desmin(-), Dog-1(+), Ki-67% <1%, and smooth muscle actin(-).

INTERVENTIONS

Surgical resection was performed on the patient.

OUTCOMES

The lesion was diagnosed as a gastric stromal tumor with a pedicle and an old hemorrhage. The patient's recovery was uneventful. After surgery, computed tomography at the 6-month and 1-year postoperative follow-up visits did not reveal relapse or any metastasis.

LESSONS

In the clinical setting, physicians should pay more attention to the pattern of manifestation of the extra-gastric stromal tumor in patients with a pedicle or hemorrhage. Additionally, endoscopic ultrasound-guided fine-needle aspiration can be used to make an accurate preoperative diagnosis of such diseases, and its findings can serve as an important basis for surgical excision of the lesions.

Ulcerated gastrointestinal stromal tumor causing a gastrogastric intussusception

When a gastrointestinal intussusception is found, an underlying lesion should be excluded.

Current clinical management of gastrointestinal stromal tumor

Gastrointestinal stromal tumors (GISTs) are the most common malignant subepithelial lesions (SELs) of the gastrointestinal tract. They originate from the interstitial cells of Cajal located within the muscle layer and are characterized by over-expression of the tyrosine kinase receptor KIT. Pathologically, diagnosis of a GIST relies on morphology and immunohistochemistry [KIT and/or discovered on gastrointestinal stromal tumor 1 (DOG1) is generally positive]. The prognosis of this disease is associated with the tumor size and mitotic index. The standard treatment of a GIST without metastasis is surgical resection. A GIST with metastasis is usually only treated by tyrosine kinase inhibitors without radical cure; thus, early diagnosis is the only way to improve its prognosis. However, a GIST is usually detected as a SEL during endoscopy, and many benign and malignant conditions may manifest as SELs. Conventional endoscopic biopsy is difficult for tumors without ulceration. Most SELs have therefore been managed without a histological diagnosis. However, a favorable prognosis of a GIST is associated with early histological diagnosis and R0 resection. Endoscopic ultrasonography (EUS) and EUS-guided fine needle aspiration (EUS-FNA) are critical for an accurate diagnosis of SELs. EUS-FNA is safe and effective in enabling an early histological diagnosis and adequate treatment. This review outlines the current evidence for the diagnosis and management of GISTs, with an emphasis on early management of small SELs.

EUS-guided sampling with 25G biopsy needle as a rescue strategy for diagnosis of small subepithelial lesions of the upper gastrointestinal tract

BACKGROUND AND STUDY AIMS

 This study was designed to evaluate the impact of additional tissue obtained with endoscopic ultrasound (EUS)-guided 25-gauge core biopsy needle (25G-PC) following an unsuccessful fine-needle biopsy (FNB) performed with larger-bore needles for the characterization of gastrointestinal subepithelial lesions (GI-SELs).

PATIENTS AND METHODS

 We prospectively collected and retrospectively analyzed information in our database from January 2013 to June 2017 for all patients with GI-SELs who received a EUS-guided FNB (EUS-FNB) with 25G-PC during the same procedure after failure of biopsy performed with larger-bore needle. Diagnostic yield, diagnostic accuracy and procedural complications were evaluated.

RESULTS

Sixteen patients were included in this study, 10 men and 6 women, median age 67.8 (range 43 to 76 years). Five patients were found to have a SEL localized in the distal duodenum, five in the gastric antrum, two in the gastric fundus and four in the gastric body. The mean size of the lesions was 20.5 mm (range 18 - 24 mm). EUS-FNB with 25G-PC enabled final diagnosis in nine patients (56.2 %). Regarding the subgroup of duodenal lesions, the procedure was successful in four of five (80 %). Final diagnoses with EUS-guided sampling were GIST (n = 6), leiomyoma (n = 2) and metastatic ovarian carcinoma (n = 1). No procedure-related complications were recorded.

CONCLUSION

 In patients with small GI-SELs, additional tissue obtained with 25G-PC could represents a "rescue" strategy after an unsuccessful procedure with larger-bore needles, especially when lesions are localized in the distal duodenum.

High clinical impact and diagnostic accuracy of EUS-guided biopsy sampling of subepithelial lesions: a prospective, comparative study

Background

In a tertiary center setting we aimed to study the diagnostic accuracy and clinical impact of EUS-guided biopsy sampling (EUS-FNB) with a reverse bevel needle compared with that of fine needle aspiration (EUS-FNA) in the work-up of subepithelial lesions (SEL).

Methods

All patients presenting with SELs referred for EUS-guided sampling were prospectively included in 2012–2015. After randomization of the first pass modality, dual sampling with both EUS-FNB and EUS-FNA was performed in each lesion. Outcome measures in an intention-to-diagnose analysis were the diagnostic accuracy, technical failures, and adverse events. The clinical impact was measured as the performance of additional diagnostic procedures post-EUS and the rate of unwarranted resections compared with a reference cohort of SELs sampled in the same institution 2006–2011.

Results

In 70 dual sampling procedures of unique lesions (size: 6–220 mm) the diagnostic sensitivity for malignancy and the overall accuracy of EUS-FNB was superior to EUS-FNA compared head-to-head (90 vs 52%, and 83 vs 49%, both p < 0.001). The adverse event rate of EUS-FNB was low (1.2%). EUS-FNB in 2012–2015 had a positive clinical impact in comparison with the reference cohort demonstrated by less cases referred for an additional diagnostic procedure, 12/83 (14%) vs 39/73 (53%), p < 0.001, and fewer unwarranted resections in cases subjected to surgery, 3/48 (6%) vs 12/35 (34%), p = 0.001.

Conclusions

EUS-FNB with a reverse bevel needle is safe and superior to EUS-FNA in providing a conclusive diagnosis of subepithelial lesions. This biopsy sampling approach facilitates a rational clinical management and accurate treatment.

Electronic supplementary material

The online version of this article (doi:10.1007/s00464-017-5808-2) contains supplementary material, which is available to authorized users.

Clinical implications of doubling time of gastrointestinal submucosal tumors

AIM

To evaluate the efficacy of doubling time (DT) of gastrointestinal submucosal tumors (GIST).

METHODS

From April 1987 through November 2012, a total of 323 patients were given a final histopathological diagnosis of GISTs on surgical resection or endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) in Kitasato University East Hospital or Kitasato University Hospital. We studied 53 of these patients (34 with resected tumors and 19 with unresected tumors) whose tumors could be measured on EUS on at least two successive occasions. The histopathological diagnosis was GIST in 34 patients, leiomyoma in 5, schwannoma in 3, ectopic pancreas in 1, hamartoma in 1, cyst in 1, Brunner’s adenoma in 1, and spindle-cell tumor in 7. We retrospectively calculated the DT of GISTs on the basis of the time course of EUS findings to estimate the growth rate of such tumors.

RESULTS

The DT was 17.2 mo for GIST, as compared with 231.2 mo for leiomyoma, 104.7 mo for schwannoma, 274.9 mo for ectopic pancreas, 61.2 mo for hamartoma, 49.0 mo for cyst, and 134.7 mo for Brunner’s adenoma. The GISTs were divided into risk classes on the basis of tumor diameters and mitotic figures (Fletcher’s classification). The classification was extremely low risk or low risk in 28 patients, intermediate risk in 3, and high risk in 3. DT of GIST according to risk was 24.0 mo for extremely low-risk plus low-risk GIST, 17.1 mo for intermediate-risk GIST, and 3.9 mo for high-risk GIST. DT of GIST was significantly shorter than that of leiomyoma plus schwannoma (P < 0.05), and DT of high-risk GIST was significantly shorter than that of extremely low-risk plus low-risk GIST (P < 0.05).

CONCLUSION

For GIST, a higher risk grade was associated with a significantly shorter DT. Small SMTs should initially be followed up within 6 mo after detection.

Gastric and small intestine gastrointestinal stromal tumors: Do outcomes differ?

BACKGROUND AND OBJECTIVES

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. Previous literature has suggested that small intestine GISTs are more aggressive than gastric GISTs. Our primary objective was to compare the outcomes of gastric and small intestine GISTs in the decade after approval of imatinib for treatment.

METHODS

The SEER database was queried for cases of gastric and small intestine GIST between the years 2002 and 2012, using the ICD-O-3 histology code 8936. Survival analysis was performed using generalized gamma models for time to cause-specific mortality (CSM).

RESULTS

CSM was 14.0% for the 3,759 gastric GIST patients and 14.3% for the 1,848 small intestine GIST patients. Five-year survival was 82.2% and 83.3% for gastric and small intestine patients, respectively. The number of diagnosed cases of GIST increased over the course of this study, especially for tumors <5 cm in size and in patients over age 50 years.

CONCLUSIONS

In this large nation-wide study, we found that patients with gastric and small intestine GISTs had similar outcomes, in contrast to previous reports. The diagnosis of GIST has significantly increased in the last decade, which may reflect the increased recognition of this entity and frequent use of imaging. J. Surg. Oncol. 2017;115:351-357. © 2016 Wiley Periodicals, Inc.

Small EUS-suspected gastrointestinal stromal tumors of the stomach: An overview for the current state of management

Gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumors found in the gastrointestinal (GI) tract, with the stomach being the most common site. They represent a distinct group of GI tumors originating from the interstitial cells of Cajal and are characterized by gain-of-function mutations of KIT. KIT oncoprotein serves as both diagnostic and therapeutic targets. Prognosis is related to size, mitotic activity, and site of the tumor. Asymptomatic, small endoscopic ultrasonography (EUS)-suspected GISTs are increasingly encountered with the wide availability of endoscopic/endosonographic examination. The majority of small GISTs are biologically indolent, albeit possibly harboring c-KIT gene mutations. An ongoing controversy exists regarding the management and surveillance policy for small gastric GISTs. A number of reports on the management of GISTs have been published, not confidently addressing the issue of gastric GISTs of small size. This work provides an overview on the current state of management considerations, specifically focusing on small EUS-suspected gastric GISTs, which are increasingly encountered by clinicians.

Current endoscopic ultrasound-guided approach to incidental subepithelial lesions: optimal or optional?

Subepithelial lesions (SEL) are identified during endoscopic procedures on a regular basis. They can occur anywhere in the gastrointestinal (GI) tract and are located beneath the normal epithelial layer, which explains why a tissue diagnosis is difficult to obtain with routine biopsies. Endoscopic ultrasound (EUS) is used to further characterize these lesions. EUS can distinguish intramural lesion from extramural compression. Furthermore, it allows allocation of intramural lesions to a specific layer of the GI wall and offers additional information as to whether a lesion could be benign or malignant. EUS also assists in choosing the optimal means of tissue acquisition. The choice of tissue acquisition is based on a number of factors, such as tumor size, EUS features, and location within the GI tract or within a specific layer of the GI wall. Furthermore, local expertise and patient factors should be considered when deciding whether tissue acquisition, surgical intervention or follow up is recommended. In this review we offer an EUS-guided approach to the evaluation of incidental SEL based on current evidence and point out areas of uncertainty, which explain why the proposed algorithmic approach may be optional rather than optimal.

Endoscopic full-thickness resection with defect closure using clips and an endoloop for gastric subepithelial tumors arising from the muscularis propria

BACKGROUND AND AIMS

This retrospective study evaluated the safety and efficacy of endoscopic full-thickness resection (eFTR) with defect closure using clips and an endoloop for the treatment of gastric subepithelial tumors (SETs) arising from the muscularis propria (MP).

METHODS

From January 2009 to December 2012, 51 patients with gastric SETs arising from the MP underwent eFTR with defect closure using clips and an endoloop. The key steps were (1) several milliliters of mixture solution was injected into the submucosa after dots were marked around the tumor; (2) a cross incision was made in the mucosa to reveal the tumor; (3) subsequently, circumferential excavation was performed as deep as the muscularis propria, and full-thickness resection of the tumor was performed with an insulated-tip knife, including its underlying MP and serosa; (4) the gastric wall defect was closed with clips and an endoloop was then placed to fix and tighten all of the clips together.

RESULTS

Successful complete resection by eFTR was achieved in 50 cases (98.0%). One case failed and was converted into a laparoscopic resection due to the tumor falling into the peritoneal cavity during the procedure. The mean procedure time was 52 min. No patients had severe complications, such as massive bleeding, delayed bleeding, peritonitis, or gastrointestinal tract leakage. The mean tumor length was 2.4 cm. Pathological diagnoses of the tumors were leiomyomas (21/51) and gastrointestinal stromal tumors (30/51). The median follow-up period after the procedure was 22.4 months (range 1-48 months), and no residual tumor or tumor recurrence was detected during the follow-up period.

CONCLUSIONS

eFTR with defect closure with clips and an endoloop appears to be a safe and effective technique for the treatment of patients with gastric SETs originating from the MP, especially for those with extraluminal growth or adhesions to the MP.

Modified fusion imaging combining CT gastrography and CT angiography: an initial experience of preoperative mapping prior to laparoscopic exogastric wedge resection of small (<3 cm) gastric submucosal lesions

PURPOSE

To evaluate the feasibility of modified fusion imaging (MFI) combining CT gastrography (CTG) and CT angiography (CTA) in the preoperative mapping and intraoperative localization of small (<3 cm) submucosal lesions (SMLs) during laparoscopic exogastric wedge resection.

METHODS

Thirty consecutive patients scheduled for laparoscopic wedge resection of small SMLs (<3 cm) were enrolled. MFI was reconstructed using a volume rendering of the arterial phase CT data acquired after gastric distension. With MFI, the possibility of preoperative mapping and feasibility for successful intraoperative localization was evaluated using intraoperative findings as the reference standard.

RESULTS

In 21 of 30 patients (70%), preoperative mapping was possible. Preoperative mapping was feasible for successful intraoperative localization in 13 of 14 patients (93%) who underwent exogastric resection.

CONCLUSIONS

MFI combining CTG and CTA is a feasible method for developing preoperative and intraoperative "road maps" for performing laparoscopic exogastric wedge resection of small SMLs.

Prediction of risk of malignancy of gastrointestinal stromal tumors by endoscopic ultrasonography

Background/Aims

The accurate preoperative prediction of the risk of malignancy of gastrointestinal stromal tumors (GISTs) is difficult. The aim of this study was to determine whether tumor size and endoscopic ultrasonography (EUS) features can preoperatively predict the risk of malignancy of medium-sized gastric GISTs.

Methods

Surgically resected, 2 to 5 cm gastric GIST patients were enrolled and retrospectively reviewed. EUS features, such as heterogeneity, hyperechoic foci, calcification, cystic change, hypoechoic foci, lobulation, and ulceration, were evaluated. Tumors were grouped in 1 cm intervals. The correlations of tumor size or EUS features with the risk of malignancy were evaluated.

Results

A total of 75 patients were enrolled. The mean tumor size was 3.43±0.92 cm. Regarding the risk of malignancy, 51 tumors (68%) had a very low risk, and 24 tumors (32%) had a moderate risk. When the tumors were divided into three groups in 1 cm intervals, the proportions of tumors with a moderate risk were not different between the groups. The preoperative EUS features also did not differ between the very low risk and the moderate risk groups.

Conclusions

Tumor size and EUS features cannot be used to preoperatively predict the risk of malignancy of medium-sized gastric GISTs. A preoperative diagnostic modality for predicting risk of malignancy is necessary to prevent the overtreatment of GISTs with a low risk of malignancy.

Gastric gastrointestinal stromal tumor smaller than 20 mm with liver metastasis

There have been no reports of gastric gastrointestinal stromal tumors (GISTs) <20 mm with distant metastasis. We report a case of a 15-mm gastric GIST with liver metastasis 1 year after surgical resection of the primary lesion. A 35-year-old man underwent routine esophagogastroduodenoscopy in July 2009. A submucosal tumor (SMT) <20 mm was incidentally detected at the posterior wall of the gastric body. Endoscopic ultrasound (EUS) indicated that it was a gastrointestinal mesenchymal tumor, including GIST, leiomyoma or schwannoma. He did not accept regular follow-up for this gastric SMT, therefore local laparoscopic excision was carried out in October 2009. The final pathological diagnosis after surgery was GIST, 15 mm in size, and a mitotic rate of 7/50 high-power fields, which did not indicate a high metastatic risk. The patient was followed up regularly without adjuvant chemotherapy. At 1 year after surgery, a space-occupying lesion ~15 mm was detected in the left lobe of the liver by abdominal ultrasound, where no mass lesion had been observed before surgery. To make a definite diagnosis of the hepatic mass lesion, EUS-guided fine-needle aspiration was performed, which demonstrated a metastatic liver tumor from a gastric GIST. Although this was a rare case, we should keep in mind that gastric GISTs do have a chance of malignant behavior, even if <20 mm.

A resected perivascular epithelioid cell tumor (PEComa) of the pancreas diagnosed using endoscopic ultrasound-guided fine-needle aspiration

Primary perivascular epithelioid cell tumors (PEComas) of the pancreas are extremely rare. We herein report our experience with a patient who had a primary PEComa of the pancreas that was diagnosed by the preoperative histopathological examination of a biopsy specimen obtained by endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA). The patient was a 43-year-old woman whose chief complaint was abdominal pain. Imaging studies revealed a pancreatic tumor. Gastrointestinal stromal tumor (GIST), solid pseudopapillary tumor and neuroendocrine tumor were considered in the differential diagnosis. A histopathological examination of a specimen of the tumor obtained using EUS-FNA showed spindle-shaped tumor cells with enlarged nuclei and eosinophilic cytoplasm. The tumor cells proliferated in a sheet-like fashion and stained positive for the melanoma-associated antigen HMB-45. A PEComa was thus diagnosed. If an adequate tumor specimen can be obtained using EUS-FNA, immunostaining may facilitate the diagnosis of extremely rare diseases and therefore assist in deciding the treatment policy.