Gastrointestinal stromal tumors/smooth muscle tumors (GISTs) primary in the omentum and mesentery: clinicopathologic and immunohistochemical study of 26 cases

A rare case of extragastrointestinal stromal tumor of vocal cord - case report

Gastrointestinal stromal tumors (GISTs) are the mesenchymal tumors of the gastrointestinal tract. Extra Gastrointestinal stromal tumors (EGISTs) are rare neoplasms that occur outside the gastrointestinal tract [1]. Miettinen et al. [2] described the first EGIST in 1999. EGIST accounts for 10% of all GISTs [3]. The main distinction between GIST and EGIST is the site of origin of the primary tumor, as GIST occurs throughout the GI tract, from the esophagus to the anus, whereas EGIST is a tumor without any connection with the intestinal wall and are reported in the retroperitoneum, mesentery, and omentum [4]. Hu et al. [5] reported a first case report of EGIST of larynx.We present a second case report of Extra-gastrointestinal stromal tumor of larynx a 47-year-old male reported to ENT Department Command Hospital Central Command Lucknow with complaints of Hoarseness. On examination found to have right vocal cord growth for which he underwent excision of right vocal cord growth. Histopathological examination showed typical of a spindle-cell GIST, showing strong immunoreactivity for CD 117, DOG1, Vimentin and CD 99. 6 months follow up post surgery with no recurrence.

Unusual location of gastrointestinal stromal tumor (GIST): A case report and literature review of greater omentum location

INTRODUCTION

Gastrointestinal stromal tumors (GISTs) represent a unique subset of neoplasms within the digestive tract. They can manifest in various organs throughout the digestive tract, ranging from the oral cavity to the anus, with a predilection for the stomach and small intestine. A distinct subtype of GISTs, known as Extra-gastrointestinal stromal tumors (EGISTs), originate outside the typical GIST organs such as the mesentery, retroperitoneum, and occasionally the omentum. EGISTs are relatively rare, accounting for <5 % of all GIST cases.

PRESENTATION OF CASE

We present the case of a 30-year-old female patient who presented with an upper abdominal mass associated with anorexia, fever, and weakness. Radiographic imaging revealed a cystic mass beneath the left hypochondrium. Exploratory laparoscopy confirmed the presence of an isolated mass adherent to the gastrocolic ligament and greater omentum. Histopathological examination confirmed GIST, characterized by spindle-shaped cells with DOG1 and CD117/C-kit expression. The patient underwent successful tumor resection and was discharged home with postoperative imatinib therapy. Follow-up at 14 months showed no recurrence.

DISCUSSION

The rarity of Gastrointestinal Stromal Tumors (GISTs) in the Greater Omentum highlights diagnostic challenges and underscores the need for further research. Immunohistochemical analysis aids in diagnosis, with Ki-67 staining indicating a high-risk classification. Surgery remains the primary treatment, with potential adjuvant therapy utilizing Imatinib mesylate.

CONCLUSION

Our case underscores the rare occurrence of GIST in the Greater Omentum. Despite their infrequency, EGISTs should be considered in intra-abdominal masses, emphasizing accurate diagnosis for appropriate management and the need for further research.

Laparoscopic-Assisted Resection for an Extra-gastrointestinal Stromal Tumor Arising From the Mesentery of the Small Intestine: A Case Report

Gastrointestinal stromal tumors (GISTs) are mesenchymal tumors that arise in the muscular or submucosal layers of the gastrointestinal tract. Extra-gastrointestinal stromal tumors (EGISTs) are rare primary entities that develop outside the digestive tract which are histologically and immunologically similar to GISTs. We present the case of a 52-year-old female diagnosed with a primary EGIST arising in the small bowel mesentery four months after undergoing hormone therapy for multiple uterine myomas. Transvaginal ultrasonography and MRI revealed a pelvic mass suspected to be a GIST. The patient was treated with laparoscopic-assisted partial resection of the small bowel. Histopathological examination of the surgical specimen confirmed the diagnosis of an EGIST. Imatinib treatment was initiated, and no clinical evidence of recurrence or metastasis was detected postoperatively. Because EGISTs are extremely rare, the differences between EGISTs and GISTs, the degree of malignancy, and prognosis have not been fully investigated. Further studies are needed to accumulate additional cases. The present case shows that laparoscopic-assisted excision can be successfully used to manage EGISTs.

Survival analysis of extragastrointestinal stromal tumors based on the SEER database: a population-based study

BACKGROUND

Extragastrointestinal stromal tumors (EGISTs) are rare mesenchymal neoplasms that originate outside the gastrointestinal tract. However, the population-level survival analysis of EGIST remains poorly grasped. Therefore, we aimed to analyze the survival of EGIST patients using the Surveillance, Epidemiology, and End Results (SEER) database.

METHODS

All patients diagnosed with GIST and EGIST between 2000 and 2019 were identified through utilization of the SEER database. Missing data were handled using multiple imputation methodology. Kaplan-Meier analyses and Cox proportional hazard models were employed to assess the influence of demographic and clinical characteristics on both overall survival (OS) and cancer-specific survival (CSS).

RESULTS

A total of 13,330 patients were enrolled in the study, comprising 12,627 diagnosed with GIST and 703 with EGIST. EGIST patients demonstrated significantly poorer OS [hazard ratio (HR) 1.732, 95% confidence interval (CI) 1.522-1.970, P < 0.001] and CSS (HR 2.167, 95% CI 1.821-2.577, P < 0.001) compared to GIST patients. The mean 1-year, 3-year, 5-year, and 10-year OS rates for EGIST patients were 78.3%, 61.9%, 50.5%, and 32.5%, respectively, with corresponding mean CSS rates of 84.3%, 70.8%, 61.3%, and 46.5%. Multivariate Cox regression analysis identified age, race, sex, grade, size, and surgical type as independent risk factors for OS in EGIST patients, while age, sex, year of diagnosis, grade, surgical type, and radiation therapy were identified as independent risk factors for CSS. Patients with EGIST who underwent surgical treatment exhibited significantly higher 5-year OS rates (49.0% vs. 39.9%, P = 0.035) and CSS rates (63.9% vs. 53.0%, P = 0.028) compared to those who did not undergo surgery.

CONCLUSIONS

EGIST patients have a poorer prognosis compared to GIST patients; however, surgical treatment has been shown to improve the prognosis.

Anal canal gastrointestinal stromal tumour (GIST)

SummaryGastrointestinal stromal tumours (GISTs) are malignant mesenchymal tumours that originate from the interstitial pacemaker cells of Cajal. They are particularly rare, comprising only 5% of all GISTs, and often present at an advanced stage. Treatment for these tumours is still a topic of debate due to their low incidence and insidious location. A woman in her mid-70s presented with rectal bleeding and anal discomfort. A 4.5×4 cm anal GIST was diagnosed. A local excision was performed and the patient was further treated with tyrosine kinase inhibitors. At a 6-month follow-up, the MRI showed that she was disease free. Anorectal GISTs are unusual and tend to be aggressive. Surgical resection is the first-line treatment for primary, localised GISTs. However, the appropriate surgical technique for these tumours is still a topic of debate. Further studies are needed to fully understand the oncologic behaviour of these rare neoplasms.

Primary extra-gastrointestinal stromal tumor of retroperitoneum: Clinicopathologic characteristics and prognosis of six cases

Aim

This study investigates the clinicopathological features and prognostic genic biomarker factors of primary retroperitoneal extra-gastrointestinal stromal tumors (EGISTs).

Methods

The clinicopathological data of six patients with primary retroperitoneal EGIST were analyzed, including cell type (epithelioid or spindle), mitoses, and the presence of intratumoral necrosis and hemorrhage. Mitoses were counted and summed from 50 high power fields (HPFs). Mutations of exons 9, 10, 11, 13, 14, and 17 of the C-kit genes and those of exons 12 and 18 of the PDGFRA gene were examined. Follow-up was performed via telephone, and all outpatient records were reviewed. The last follow-up date was February 2022, the median follow-up was 27.5m and the postoperative status, medication, and survival of the patients were recorded.

Result

The patients were treated with radical intent. Four cases (patients 3, 4, 5, and 6) underwent multivisceral resection for encroachment on the adjacent viscera. The postoperative pathological results demonstrated that all biopsy specimens were negative for S-100 and desmin, and positive for DOG1 and CD117. Additionally, four patients (case 1, 2, 4, and 5) were positive for CD34, four (case 1, 3, 5, and 6) were positive for SMA, four (case 1, 4, 5, and 6) had >5/50 HPFs, and three (case 1, 4, and 5) had Ki67 >5%. According to the modified National Institutes of Health (NIH) guidelines, all patients were graded as high-risk cases. By exome sequencing, exon11 mutations were detected in the six patients, while exon10 mutations were detected in two cases (patients 4 and 5). The median follow-up time was 30.5 (11-109) months, with only one fatality at 11 months.

Conclusion

Retroperitoneal EGIST is a rare mesenchymal tumor that is difficult to distinguish from other retroperitoneal tumors. To diagnose this highly malignant tumor, low-threshold suspicion is necessary, and Kit and PDGFRA gene mutations should be routinely tested to confirm the diagnosis and guide subsequent treatment.

KIT (CD117) Positive Huge Primary Malignant Extra Gastrointestinal Stromal Tumors (EGISTs) Arising From Jejunal Mesentery: A Rare Case Report

Tumors arising outside gastrointestinal systems are known as extra gastrointestinal stromal tumors (EGISTs). Outside gastrointestinal sites include the mesentery, omentum, peritoneum, pancreas, and liver. Our case highlights a rare occurrence of an EGIST in jejunal mesentery in a 45-year-old male with an asymptomatic large abdominal growth and weight loss. A contrast-enhanced multi-dimensional computed tomography scan showed a large heterogeneous mass in the left hypochondrium. lumbar, and paraumbilical regions. Later, the patient underwent surgical resection of the tumor along with the involved jejunal segment and small tumor masses in the mesentery. Histopathological examination reported a malignant EGIST of mesentery and invasion into the jejunum, further confirmed by immunohistochemistry (IHC) markers like CD117 and smooth muscle actin with a high proliferative index (Ki67). One should be aware that these are different from other malignancies arising from the mesentery. Their cell of origin is different and needs a specific type of treatment. The clinical history, radiological findings, histopathology, and IHC help in diagnosing especially when they are arising from unusual areas like jejunal mesentery. Surgical intervention and chemotherapy are mainstay treatments.

CT, MR, and CEUS imaging features of recurrent GIST of the pre-sacral space: A case report

We present the case of a 50-year-old woman affected by a rectal gastrointestinal stromal tumor (GIST), with a recurrence in pre-sacral and pre-coccygeal space after surgery and Imatinib therapy. GISTs are the most common mesenchymal tumors of the gastrointestinal tract and rectal GISTs are rare (only 2% of cases); magnetic resonance and computed tomography are the main imaging techniques for diagnosis and follow-up, while ultrasound and contrast-enhanced ultrasound may be useful to perform a percutaneous biopsy, as in the case presented: the imaging features of the lesion in all these imaging methods are displayed.

Laparoscopic resection for spontaneously ruptured primary extragastrointestinal stromal tumor of the greater omentum: A case report

Introduction

Ruptured extragastrointestinal stromal tumor (EGIST) are rare; therefore, there are no standard guidelines for its treatment. Herein, we report the successful laparoscopic resection of a ruptured EGIST.

Presentation of case

The patient was a 59-year-old man, a Jehovah's Witness, who presented with sudden onset of left-sided abdominal pain. Contrast-enhanced computed tomography (CECT) performed from a previous hospital revealed intra-abdominal hemorrhage. Repeat CECT at our institution revealed extravasation and serum ascites. A hematoma was found anterior to the omentum, and a tumor was detected which did not have continuity with the surrounding organs of the gastrointestinal tract. Complete tumor resection via laparoscopic surgery was performed and the specimen was sent for histopathology, which revealed bundle-like proliferation of spindle-shaped cells. Immunohistochemical staining was completed, which was positive for KIT and CD34. Based on surgical and pathological findings, the final diagnosis was extragastrointestinal stromal tumor originating from the omentum.

Discussion

EGISTs have a similar morphology to that of gastrointestinal stromal tumors, but instead, arise outside the gastrointestinal tract. A significant differentiation and key to the diagnosis of EGIST is the absence of continuity with the gastrointestinal tract. The preferred treatment for EGIST is complete surgical resection, and the use of laparoscopy has not been well studied. Postoperative histopathological examination, along with immunohistochemical staining, aid confirmatory diagnosis.

Conclusion

Laparoscopic removal of EGISTs is a minimally invasive and potentially useful technique for the management of this tumor type.

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Diagnosis and treatment of a spontaneously ruptured tumor is complicated.

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Religion restrictions in management should be respected and followed.

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First line of treatment of EGISTs is complete surgical resection.

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Laparoscopic removal of EGISTs is minimally invasive and potentially useful.

Extra-gastrointestinal stromal tumor of the pancreas: A case report

Introduction

Presentation of case

Clinical discussion

Conclusion

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Pancreatic EGIST is extremely rare.

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There are no specific clinical and radiologic findings.

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Surgical resection is the cornerstone of the treatment.

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Whenever possible, enucleation is sufficient.

DOG1-Positive Primary Mesenteric Leiomyosarcoma: Report of a Case and Review of the Literature

The mesentery constitutes a common location for the metastatic spread of malignant gastrointestinal tumors. Primary mesenteric tumors, on the other hand, are very rare; lymphomas are the most common, followed by benign and malignant mesenchymal tumors. We present a case of a 43-year-old patient operated on for a primary mesenteric leiomyosarcoma with a positive immunostain for DOG1, despite having no KIT or PDGFRa mutations on molecular analysis. Moreover, we review the pertinent literature. 

Extremely Aggressive Mesenteric Extragastrointestinal Stromal Tumor: A Case Report and Literature Review

Gastrointestinal stromal tumors (GISTs) are rare tumors with increasing incidence. GIST is the most common mesenchymal tumor of the gastrointestinal tract involving the elderly population with a slow progression. It originates from the interstitial cells of Cajal. GISTs that develop outside the gastrointestinal tract and have no connections with the intestinal walls or serosal surfaces of the gastrointestinal tubular organs are referred to as extraintestinal gastrointestinal stromal tumors (EGISTs). They have similar morphological and immunohistological characteristics as GISTs. Here, we describe a unique case of an extremely aggressive mesenteric GIST in a 44-year-old African American male.

The patient presented to the hospital with complaints of generalized abdominal pain associated with 50-pound weight loss, decreased appetite, and constipation. He underwent computed tomography (CT) of the abdomen and pelvis which showed a large mass along the central mesentery measuring about 15 × 11 cm with adjacent metastatic nodal disease. He underwent a CT-guided biopsy of his abdominal mass with histopathology findings positive for c-kit (CD117) and discovered on GIST-1 (DOG-1) consistent with GIST. Based on TNM staging, his tumor was graded T4 with N1 given nodal involvement placing him as a stage IV. He was referred to an oncologist and was started on neoadjuvant therapy with imatinib. Mesenteric EGISTs, while rare, are known to have a worse prognosis compared to other EGISTs; hence, prompt action must be taken in aggressively treating these tumors. Factors such as mitotic index and tumor size affect the prognosis of mesenteric GISTs.

Primary gastrointestinal stromal tumor of the left hepatic lobe: a case report and a review of the literature

Gastrointestinal stromal tumors (GISTs) can arise from any site of the gastrointestinal tract. These tumors are known to originate from the interstitial cells of Cajal, located in the gastrointestinal mesenchyme. In the case presented, a 37-year-old Caucasian male was admitted to our Surgery department with 2-month history of mild abdominal pain, early satiety and flatulence. The computed tomography revealed a huge mass in the left hepatic lobe consisting of both spindle and epithelial cells. Immunohistochemistry revealed strong CD117 positivity expression. Only a few other cases of liver GIST have been reported in the literature.

Whole-exome sequencing for high-risk primary prostatic extra-gastrointestinal stromal tumor: A case report

The low incidence rates of prostatic extra-gastrointestinal stromal tumors (EGIST), combined with the lack of published guidelines on its treatment, often results in its misdiagnosis and challenges in the treatment of patients, even in cases with high-risk factors. The present case study reported a 65-years-old Chinese male patient, who presented with intermittent hematuria and lower urinary tract symptoms for three months. The colonoscopy results revealed no gastrointestinal lesions; however, a core biopsy diagnosed an EGIST, which subsequently underwent radical prostatocystotomy, standard pelvic lymph node resection, and bricker ileal conduit diversion. The postoperative pathological results suggested a high-risk primary prostatic EGIST, according to the aggressive behavior of the GIST. The immunohistochemistry results revealed the positive expression of CD117, DOG1, CD34, androgen receptor AR, prostate-specific antigen (PSA), a 2% Ki-67 index and a positive surgical margin. The whole exome sequencing (WES) results revealed that the patient harbored a single nucleotide mutation in 121 genes and copy number variations in 601 genes, including a defect in c-Kit (in-frame deletion in p.Q556-V560; fold, 17.5%). By compiling the data obtained from the ConsensusPathDB and the drug-gene interaction databases and expert opinions, the patient was prescribed with the personalized drugs (400 mg per day imatinib mesylate and 50 mg per day bicalutamide, which were stopped when the PSA levels remained stable below 0.01 ng/ml) for 18 months follow-up and there were no signs of recurrence. In conclusion, WES identified multiple genomic alterations and the underlying genetic defect in the rare case enabled the evaluation of the prognosis and the decision of potential drug candidates. The underlying mechanism of the substantial genetic variations in the primary prostatic EGIST, as well as the malignant behaviors of the tumor, remain to be investigated.

MRI, CT and FDG-PET/CT findings of Wolffian tumor: four-case series

Purpose

The purpose of this study is to describe the characteristic MRI, CT, and ¹⁸F-fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) findings of Wolffian tumor.

Methods

We reviewed preoperative images in four surgical cases of Wolffian tumor. MRI was available for review in all cases with additional diffusion-weighted images (DWI) in three, and contrast-enhanced images in two. CT was available in three. FDG-PET/CT was obtained in two.

Results

Two patients were asymptomatic, while the other two presented with acute abdomen. On MRI, all tumors were well-defined masses of increased signals on T2WI. Three tumors were solid, whereas the other was solid and cystic. The normal ipsilateral ovary was identified in two patients of reproductive ages, but not in two postmenopausal patients. Tumors in two patients presented with acute abdomen were complicated by hemorrhage. All three tumors evaluated on DWI showed high intensities. Contrast-enhanced images of MRI and CT showed homogeneous enhancement as the same degree as the myometrium. On CT, one tumor contained punctate calcifications. FDG-PET/CT showed moderate FDG accumulation.

Conclusion

Wolffian tumors may be typically solid extraovarian tumors occasionally associated with cysts and calcifications. Although they are benign, they mimic malignancy due to high intensities on DWI and increased FDG accumulation.

Gastrointestinal Stromal Tumor as a Rare Cause of Abdominal Mass: A Case Report and Literature Review

Gastrointestinal stromal tumors (GISTs) are soft tissue sarcomas that can arise from any part of the digestive system. GISTs represent 1% of gastric neoplasms. We report a rare case of a GIST tumor in a 59-year-old woman who presented with abdominal pain and weight loss. Computed tomography (CT) of the abdomen with intravenous contrast revealed a left upper quadrant abdominal mass and biopsy showed GIST. She was treated with imatinib to downsize the tumor prior to undergoing surgical resection of the tumor.

Rectovaginal extragastrointestinal stromal tumour (EGIST): an additional entity to be considered in the differential diagnosis of tumours of the rectovaginal septum

Gastrointestinal stromal tumours (GISTs) are rare - and rectovaginal extragastrointestinal stromal tumours (RV-EGISTs) even rarer. We share a case of RV-EGIST, complemented by high-quality radiological and surgical images. A review of current literature pertaining to RV-EGIST is also included. Our case report highlights the diagnostic challenge presented by extragastrointestinal stromal tumours. Differentiated from overlapping pathologies only by targeted application of immunohistopathology and cytogenetics, the inclusion of RV-EGIST in the differential diagnosis of a rectovaginal tumour is essential to making this correct diagnosis. Primary surgery is the treatment of choice for RV-EGIST if complete cytoreduction can be achieved, combined with adjuvant tyrosine kinase inhibitor (TKI) therapy for those with high-risk features to further reduce rates of future recurrence.

Extra-gastrointestinal stromal tumor presenting as a huge peritoneal mass and mimicking as mesothelioma - A case report

INTRODUCTION AND IMPORTANCE

Extra-gastrointestinal stromal tumors are group of soft tissue neoplasm, which originates outside the gastrointestinal tract comprising of less than 5% of the total gastrointestinal stromal tumors.

CASE PRESENTATION

A 67 years old male came with a history of vague abdominal pain, discomfort and loss of appetite. Per abdominal examination showed a palpable firm mass which was filling both the flanks. Radiological imaging revealed a large abdomino-pelvic mass with central necrotic areas. Exploratory laparotomy was done and the mass was excised intact from the sigmoid mesocolon. Histopathological diagnosis was given as extra-gastrointestinal stromal tumors.

CLINICAL DISCUSSION

Extra-gastrointestinal stromal tumor was first described by Miettinen et al. in 1999. The tumor can arise from the pleura, omentum, mesentery, retroperitoneum and prostate. The clinical presentation of the tumor depends on its location and the size of tumor. Patients with these tumors present with abdominal pain, followed by abdominal mass and distention. These tumors show pathological, immunohistochemical and molecular biological characters similar as that of gastrointestinal stromal tumor.

CONCLUSION

Extra-gastrointestinal stromal tumor is a rare tumor and can reach to a considerable large size before presenting with clinical symptoms especially if the tumor arises from the mesocolon. IHC study plays an important role to reach to the final diagnosis as the tumor can mimic mesothelioma in routine staining.

Imaging in gynecological disease (19): clinical and ultrasound features of extragastrointestinal stromal tumors (eGIST)

OBJECTIVE

To describe the clinical and sonographic characteristics of extragastrointestinal stromal tumors (eGISTs).

METHODS

This was a retrospective multicenter study. The data of patients with a histological diagnosis of eGIST who had undergone preoperative ultrasound examination were retrieved from the databases of nine large European gynecologic oncology centers. One investigator from each center reviewed stored images and ultrasound reports, and described the lesions using the terminology of the International Ovarian Tumor Analysis and Morphological Uterus Sonographic Assessment groups, following a predefined ultrasound evaluation form. Clinical, surgical and pathological information was also recorded.

RESULTS

Thirty-five women with an eGIST were identified; in 17 cases, the findings were incidental, and 18 cases were symptomatic. Median age was 57 years (range, 21-85 years). Tumor marker CA 125 was available in 23 (65.7%) patients, with a median level of 23 U/mL (range, 7-403 U/mL). The vast majority of eGISTs were intraperitoneal lesions (n = 32 (91.4%)); the remaining lesions were retroperitoneal (n = 2 (5.7%)) or preperitoneal (n = 1 (2.9%)). The most common site of the tumor was the abdomen (n = 23 (65.7%)), and less frequently the pelvis (n = 12 (34.3%)). eGISTs were typically large (median largest diameter, 79 mm) solid (n = 31 (88.6%)) tumors, and were less frequently multilocular-solid tumors (n = 4 (11.4%)). The echogenicity of solid tumors was uniform in 8/31 (25.8%) cases, which were all hypoechogenic. Twenty-three solid eGISTs were non-uniform, either with mixed echogenicity (9/23 (39.1%)) or with cystic areas (14/23 (60.9%)). The tumor shape was mainly lobular (n = 19 (54.3%)) or irregular (n = 10 (28.6%)). Tumors were typically richly vascularized (color score of 3 or 4, n = 31 (88.6%)) with no shadowing (n = 31 (88.6%)). Based on pattern recognition, eGISTs were usually correctly classified as a malignant lesion in the ultrasound reports (n = 32 (91.4%)), and the specific diagnosis of eGIST was the most frequent differential diagnosis (n = 16 (45.7%)), followed by primary ovarian cancer (n = 5 (14.3%)), lymphoma (n = 2 (5.7%)) and pedunculated uterine fibroid (n = 2 (5.7%)).

CONCLUSIONS

On ultrasound, eGISTs were usually solid, non-uniform pelvic or abdominal lobular tumors of mixed echogenicity, with or without cystic areas, with rich vascularization and no shadowing. The presence of a tumor with these features, without connection to the bowel wall, and not originating from the uterus or adnexa, is highly suspicious for eGIST. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

Retroperitoneal Extragastrointestinal Stromal Tumors Have a Poor Survival Outcome: A Multicenter Observational Study

Purpose

Gastrointestinal stromal tumors (GISTs) are commonly known to be derived from the gastrointestinal (GI) tract, but recently there have been more and more literature describing lesions with similar pathological and immunohistochemical resembling GISTs but located outside the GI tract, and they have been termed as extra-GISTs (eGISTs). However, due to the rare incidence of eGISTs, its association with survival outcomes is poorly understood, especially in the Chinese population. Here, we aimed to identify the risk factors of eGISTs and to assess their association with overall survival (OS) and disease-free survival (DFS).

Patients and Methods

Data of pathologically confirmed eGISTs cases, without radiological and perioperative evidence of other primary lesions, and with no microscopically identified adhesion between the tumor and the gastrointestinal serosa, which were surgically treated between January 2006 and September 2017 were retrieved from the database of four high-volume hospitals. Immunohistochemical and genetic testing were performed on the postoperative lesions and were staged using the National Institutes of Health (NIH) criteria.

Results

A total of 55 cases were retrieved. eGISTs were identified from the retroperitoneum (36.4%), mesocolon (25.5%), small bowel mesentery (12.7%), abdominopelvic cavity (12.7%), lesser omental sac (5.5%), ovary (3.6%), pancreatic capsule (1.8%), or urinary bladder (1.8%). Based on the NIH risk classification, majority of the lesion were classified as high risk (85.5%). KIT 11 was the most common mutation site (76.5%) and 25.0% of the cases were wild-type eGISTs. Multivariate analyses showed that tumor location and size were independent factors affecting prognoses. Patients with tumors in the retroperitoneum had significantly poorer OS and DFS as compared to those in the non-retroperitoneum (HR [95% CI] for OS and DFS: 2.546 [1.023–6.337] [P = 0.037] and 2.475 [0.975–6.273] [P = 0.049], respectively). Similar findings were found for tumors of size >15 cm, compared to ≤15 cm (HR [95% CI] for OS and DFS: 5.350 [2.022–14.156] [P < 0.001] and 3.861 [1.493–9.988] [P = 0.003], respectively).

Conclusion

eGISTs were predominantly found from the retroperitoneum and mostly classified as high risk. Those located in the retroperitoneum and of size >15 cm had the poorer OS and DFS as compared to those in the non-retroperitoneum and of size <15 cm.

Primary Leiomyosarcoma of the Mesentery: A Case Report With Review of Literature

Mesenteric leiomyosarcoma (LMS) is a rare gastrointestinal mesenchymal tumor. It was often misdiagnosed as a gastrointestinal stromal tumor (GIST) until the introduction of immunohistochemistry staining (IHC) in 1998. Currently, a positive IHC staining for smooth muscle markers represents the main diagnostic modality. Herein, we present a case of Mesenteric LMS in a 68-year-old woman, who presented with nausea, vomiting, and abdominal pain and was found to have a right-sided mesenteric tumor encasing the right ureter, with right hydroureteronephrosis. The patient underwent surgical removal of the tumor and IHC stains were compatible with LMS. She achieved remission until she developed recurrence 12 months after initial diagnosis and subsequently expired due to postoperative complications when re-resection was attempted. Typically, mesenteric LMS carries a poor prognosis with a propensity for hematogenous metastasis. In the absence of a standardized protocol for therapy, early surgical resection is the only known curative modality but with a high risk of recurrence.

Giant solitary fibrous tumor of the pelvis: A case report and review of literature

INTRODUCTION

Solitary fibrous tumors (SFTs) are rare spindle cells neoplasms most likely arising from mesenchymal cells. Usually they involve the pleura. Even if extra-thoracic SFTs are rare, lately they are diagnosed with increased frequency.

CASE PRESENTATION

We describe the case of giant pelvic and retroperitoneal neoplasm, a rare solitary fibrous tumor, in a 51-year-old man that was admitted for abdominal pain.

DISCUSSION

On CT a SFT appears usually as a smooth, lobulated mass with occasional calcifications, but the imaging differential diagnosis with other mesenchymal tumors is very difficult, if not impossible.

CONCLUSION

The histological and immune-histochemical features of SFTs are helpful for the differential diagnosis. The malignant potential of this cancer is low, but it is very important to perform an optimized surgery and a close follow up in the patient. We believe that this case is particularly interesting and complex because of the difficulty of predicting the future biological behavior.

Extragastrointestinal stromal tumor presenting as a scrotal mass: First report from India

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Gastrointestinal Stromal tumours (GIST) are the most common mesenchymal tumors that arises from the wall of the gastrointestinal tract.

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Similar tumours elsewhere in the abdomen are called extra gastrointestinal stromal tumor (EGIST).

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We describe an unusual case of EGIST presenting as a primary scrotal mass.

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Left inguinal orchidectomy along with excision of mass was done.

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HPE revealed a spindle cell pattern with low cellularity and IHC analysis revealed the tumor reactive for CD117 and CD34 which is suggestive of GIST.

Introduction

Gastrointestinal Stromal Tumours (GIST) are the most common mesenchymal tumours that arises from the wall of the gastrointestinal tract. Similar tumours elsewhere in the abdomen are called extra gastrointestinal stromal tumor (EGIST).

Presentation of case

A 68 years male presented with a gradually enlarging scrotal mass over a period of 6month duration. On examination a mass was felt (5 cm × 4 cm) occupying left side of scrotum and abutting the lower pole of left testis. Left inguinal orchidectomy along with excision of mass was done. HPE revealed a spindle cell pattern with low cellularity and Immunohistochemical analysis revealed the tumor reactive for CD 117 and CD 34 which is suggestive of GIST.

Discussion

EGIST have been reported in unusual locations, including the pancreas, prostate, and abdominal wall. The occurrence of EGIST is extremely rare and little is known about their actual origin. The diagnosis is by the demonstration of a specific marker CD 117 and CD34. We describe an unusual case of extra gastrointestinal stromal tumor (EGIST) presenting as a primary scrotal mass.

Conclusion

To the best of our knowledge, this is the first Indian case of an EGIST involving the scrotum as primary site and second such case worldwide.

Extra-gastrointestinal stromal tumor arising in the lesser omentum with a platelet-derived growth factor receptor alpha (PDGFRA) mutation: a case report and literature review

BACKGROUND

Gastrointestinal stromal tumors (GIST) arising from sites other than the gastrointestinal (GI) tract, termed extra-gastrointestinal stromal tumors (EGIST), are rare. Among EGIST, those with platelet-derived growth factor receptor alpha (PDGFRA) mutations are even rarer, with only a few cases reported. About 80% of GIST has KIT mutations, and 10% of GIST have PDGFRA mutations, which commonly affect the TK2 domain (exon 18). Among the exon 18 mutations, the D842V substitution is limited to gastric GIST. In EGIST, the degree of KIT and PDGFRA mutations varies on where the location of the tumor is, and it is suggested that omental EGIST is similar to gastric GIST. Adjuvant imatinib therapy is recommended for high-risk GIST; however, it is known that imatinib is less effective against GIST with a PDGFRA D842V mutation.

CASE PRESENTATION

A 75-year-old man was referred to our hospital with an extrinsic tumor of the lesser curvature of the gastric body. Intraoperative findings showed a tumor located outside of the lesser omentum with no connection between the tumor and the gastric wall. The tumor was subsequently resected. Pathological examination indicated a GIST arising in the lesser omentum measuring 70 mm in its longer dimension. Because the tumor had a PDGFRA mutation (D842V substitution), imatinib was suspected to lack efficacy to the tumor. Thus, although the tumor was considered clinically to have a high risk of recurrence, adjuvant imatinib therapy was not indicated. The patient has been free of recurrence for 29 months since the surgery.

CONCLUSION

We described a case of EGIST with a PDGFRA mutation arising in the lesser omentum. And we reviewed 57 cases of omental EGIST and showed that the clinicopathological characteristics and mutation status in omental EGIST were very similar to gastric GIST. In particular, PDGFAR D842V mutation rate in omental EGIST seemed as high as that in gastric GIST. These results suggested that omental EGIST is strongly related to gastric GIST, so the behavior of omental EGIST might be akin to gastric GIST. However, further studies are required to determine the prognosis and the necessity of adjuvant therapy for EGIST with a PDGFRA mutation.

Primary Gastrointestinal Stromal Tumor Presenting as an Isolated Lung Mass

Gastrointestinal stromal tumors (GISTs) are rare gastrointestinal (GI) tumors, representing a small portion of soft tissue tumors of the abdominal cavity. Extraintestinal gastrointestinal stromal tumors (EGISTs) are uncommon forms of GISTs that present outside the GI tract. There have only been a rare number of reported cases of EGIST presenting above the diaphragm. We present the case of a 50-year-old female with shortness of breath, and found to have bilateral pleural effusions and left-sided lung mass. The initial lung mass aspiration was negative for malignancy; yet, pleural fluid was suggestive of malignancy, and repeat biopsy and immunohistochemical stain were diagnostic for GIST. Ultimately, the patient underwent video-assisted thoracoscopic surgery, pleurodesis with doxycycline, and adjuvant therapy with imatinib. This is a report of primary EGIST presenting as an isolated lung lesion with no involvement of the GI tract. In patients with suspected malignancy, it is of paramount importance to obtain a detailed history, including remote signs and symptoms, while performing a thorough work-up. Especially in the lung where initial biopsies can be skewed due to inflammation and atelectasis, repeat biopsies may be necessary to obtain an accurate diagnosis.

Current management of succinate dehydrogenase-deficient gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GISTs) are increasingly recognized as having diverse biology. With the development of tyrosine kinase inhibitors molecularly matched to oncogenic KIT and PDGFRA mutations, GISTs have become a quintessential model for precision oncology. However, about 5-10% of GIST lack these driver mutations and are deficient in succinate dehydrogenase (SDH), an enzyme that converts succinate to fumarate. SDH deficiency leads to accumulation of succinate, an oncometabolite that promotes tumorigenesis. SDH-deficient GISTs are clinically unique in that they generally affect younger patients and are associated with GIST-paraganglioma hereditary syndrome, also known as Carney-Stratakis Syndrome. SDH-deficient GISTs are generally resistant to tyrosine-kinase inhibitors, the standard treatment for advanced or metastatic GIST. Thus, surgical resection is the mainstay of treatment for localized disease, but recurrence is common. Clinical trials are currently underway investigating systemic agents for treatment of advanced SDH-deficient GIST. However, further studies are warranted to improve our understanding of SDH-deficient GIST disease biology, natural history, surgical approaches, and novel therapeutics.

Gastrointestinal Stromal Tumors of Small Intestine

Gastrointestinal stromal tumor (GIST) is defined as mesenchymal tumors of the gastrointestinal tract expressing proto-oncogene protein CD117. They are the most common sarcomatous tumors of the gastrointestinal tract. GISTs are presumed to arise from interstitial cells of Cajal or gastrointestinal pacemaker cells which control gut motility. They have unpredictable biological behavior. Prognosis is dependent on tumor size as well as mitotic count. Radical surgical excision is the treatment of choice. They rarely metastasize to lymph nodes. Imatinib therapy is used as an adjuvant therapy. The follow-up of patients postsurgery is not standardized.

New frontiers in the medical management of gastrointestinal stromal tumours

The tyrosine kinase inhibitor (TKI) imatinib has radically changed the natural history of KIT-driven gastrointestinal stromal tumours (GISTs). Approved second-line and third-line medical therapies are represented by the TKIs sunitinib and regorafenib, respectively. While imatinib remains the cardinal drug for patients with GISTs, novel therapies are being developed and clinically tested to overcome the mechanisms of resistance after treatments with the approved TKI, or to treat subsets of GISTs driven by rarer molecular events. Here, we review the therapy of GISTs, with a particular focus on the newest drugs in advanced phases of clinical testing that might soon change the current therapeutic algorithm.

Primary hepatic gastrointestinal stromal tumor with right adrenal gland invasion: A case report and systematic literature review

INTRODUCTION

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors that mainly occur in the gastrointestinal tract. The GISTs that are sporadically reported in extra-gastrointestinal regions are named as extra-gastrointestinal stromal tumors (EGISTs). However, the primary EGISTs that originate from the liver are rare.

PATIENT CONCERNS

A 64-year-old female presenting with right upper abdominal pain and thirsty for more than 20 days.

DIAGNOSIS

A diagnosis of a 15 × 14 × 7 cm liver mass located in the posterior right lobe of liver and spread to the right adrenal gland was confirmed. Pathological results showed that the tumor was mainly composed of epithelial cells and tested positive for CD117 and SDHB (succinate dehydrogenase complex iron sulfur subunit B). The gene mutational analyses for c-Kit and platelet-derived growth factor receptor alpha exons revealed negative results. Fluorescence in situ hybridization of murine double minute 2 produced negative fluorescence results which distinguished it from dedifferentiated liposarcomas. The postoperative gastroduodenal and colorectal endoscopy did not find any neoplastic lesions. To this end, the diagnosis of primary hepatic EGIST of wild type nature was confirmed.

INTERVENTIONS

The patient received right hepatectomy and adrenalectomy, no postoperative chemotherapy was administered.

OUTCOMES

The patient died 11 months after surgery due to tumor metastasis.

CONCLUSION

Primary hepatic EGIST is a rare and complicated disease of liver, a multidisciplinary team is necessary in diagnosis and treatment of primary hepatic EGIST.

Extra-gastrointestinal stromal tumor with a large cyst

Gastrointestinal stromal tumors (GISTs) arising at sites other than the alimentary tract are rare, and they are called extra-GISTs (EGISTs). We report a case of a large EGIST forming a cyst, probably arising in the mesentery of the transverse colon. A 64-year-old Japanese man presented to a hospital with an abdominal tumor forming a large cyst. Intraoperatively, the tumor was neither present in nor in contact with the alimentary tract. It was present in the mesentery of the transverse colon and was attached to the greater omentum and peritoneum, immediately anterior to the body of the pancreas. The tumor was resected with the spleen and a part of the pancreas. Histological examination of the tumor revealed that it belonged to the high-risk category of cystic EGISTs.

Role of PLK1 signaling pathway genes in gastrointestinal stromal tumors

In previous studies by the authors, aurora kinase A (AURKA) was demonstrated as an independent poor prognostic marker for the recurrence of localized gastrointestinal stromal tumors (GISTs) and for the progression of advanced GISTs. In the present study, the prognostic effect of genes involved in cell cycle regulation in GISTs was further examined. Leading edge analysis in gene set enrichment analysis was used to identify the most common genes in the top 10 enriched gene sets of high-risk patients with GISTs in a Japanese study. The obtained gene list was uploaded to the Pathway Interaction Database to search for critical pathways. Selected genes within the pathway were subsequently verified through immunohistochemistry (IHC) in another cohort of patients. A total of 5 genes in 'PLK1 signaling events,' namely AURKA, polo-like kinase 1 (PLK1), cell division cycle 25C (CDC25C), budding uninhibited by benzimidazoles (BUB1), and targeting protein for Xklp2 (TPX2), were identified for subsequent study. Among the Japanese cohort, all 5 genes, except BUB1, were significant prognostic factors for poor recurrence-free survival (RFS). Among 141 patients enrolled for the IHC study, all 5 genes exhibited variable expression patterns. In the association study, only AURKA exhibited significant overexpression in non-gastric tumors. Although all 5 genes were considered as risk factors for poor RFS based on a univariate analysis, only the mitotic count and expression levels of CDC25C, BUB1, and TPX2 retained prognostic effects in the multivariate analysis. The PLK1 signaling pathway is crucial in the disease progression of GISTs. Genes within this pathway may serve as predictive markers for adjuvant therapy.

Extragastrointestinal Stromal Tumor (EGIST): A 16-Year Experience of 13 Cases Diagnosed at a Single Center

Background

Gastrointestinal stromal tumor (GISTs) rarely occurs outside the GI tract as extragastrointestinal stromal tumor (EGIST). The aim of this study was to review the clinical presentation, diagnosis, and outcome of EGIST at a single center.

Material/Methods

The study was a retrospective study performed at Istanbul University Hospital in a 16-year period and included patients with a histopathological diagnosis of EGIST confirmed to arise outside the GI tract. The patients’ available medical records included patient demographics, imaging and surgical data, and diagnostic histopathology reports. Cases of EGIST underwent follow-up for several years and the medical files of patients were well maintained.

Results

Thirteen cases of EGIST included six women and seven men, with a mean age of 59.6 years (range, 33–83 years). Eleven patients had EGISTs located in the intra-abdominal cavity, one patient’s tumor was in the retroperitoneum, and in the jejunal mesentery in one patient. The mean diameter of the EGISTs was 15.6 cm (range, 4–30 cm). Immunohistochemistry showed that all cases were negative for desmin, with positive immunostaining for CD34 (n=6), smooth muscle actin (SMA) (n=3), and Ki67 (n=6), without specific diagnostic markers. Following surgical resection, tumor recurrence occurred in three patients, and metastasis in two patients. The mean overall survival (OS) was 45.66 months (56.44 months for women; 32.57 months for men); the 5-year survival rate of our patients was 38%.

Conclusions

EGIST presented with a large tumor size at diagnosis, was mainly intra-abdominal, and had a low mean patient survival time with no specific diagnostic tissue immunomarkers.

Extragastrointestinal stromal tumors of the pelvic cavity and the vagina: Two case reports and review of the literature

Gastrointestinal stromal tumors (GISTs) are rare tumors of gastrointestinal (GI) tract with mesenchymal cell origin. Extragastrointestinal stromal tumors (EGISTs) are unusual tumors that exhibit the same immunohistochemical and genetic abnormalities as GISTs and most commonly affect the omentum and mesentery. EGISTs of the pelvis and the female reproductive system are exceedingly rare and a frequent diagnostic pitfall. In this report, we present two cases of EGISTs along with a review of the literature.

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All pelvic and vaginal EGISTs summarized

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Presentation of pelvic EGISTs is nonspecific leading to delay in diagnosis.

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Surgery +/− imatinib potentially curative for vaginal and pelvic EGISTs.

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C-kit testing is essential to differentiate EGISTs from other gynecological tumors.

Clinicopathological features and prognosis of mesenteric gastrointestinal stromal tumor: evaluation of a pooled case series

Background

Due to the extremely rare incidence, data of clinicopathological features and prognosis of mesenteric gastrointestinal stromal tumors (GISTs) are limited. Therefore, the aim of the present study was to investigate the clinicopathological features and prognosis of mesenteric GISTs.

Patients and Methods

Mesenteric GISTs cases were obtained from our center and from case reports and clinical series extracted from MEDLINE. Clinicopathological features and survivals were analyzed.

Results

A total of 114 mesenteric GISTs were enrolled in present study. The most common symptom was abdominal pain (20/72, 27.8%), followed by abdominal mass (13/72, 18.1%) and distention (9/72, 12.5%). Most tumors exceeded 10 cm in diameter (71/112, 63.4%), exceeded 5/50HPF in mitotic index (50/85, 58.8%), and were high risk (82/90, 91.1%). The five-year disease free survival (DFS) and disease specific survival (DSS) was 57.7% and 60.1%, respectively. Tumor size and mitotic index were associated with DFS and DSS. The distribution of tumor size, histological type, mitotic index and NIH risk category were significantly different between mesenteric and gastric GISTs. Prognosis of mesenteric GISTs was worse than that of gastric GISTs. However, multivariate analysis showed that location was not an independent prognostic factor for mesenteric and gastric GISTs.

Conclusions

Most mesenteric GISTs exceeded 10 cm in diameter, exceeded 5/50HPF in mitotic index and were high risk. Mesenteric GISTs differed significantly from gastric GISTs in respect to clinicopathologic features. Mitotic index and tumor size were prognostic factors for mesenteric GISTs. The prognosis were comparable between mesenteric and gastric GISTs.

Management of rectal gastrointestinal stromal tumor

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal neoplasm of the gastrointestinal tract. However, rectal GIST is rare, the incident rate of it is approximately 5% of all GISTs. Rectal GIST symptoms generally include bleeding and/or pain and occasionally, urinary symptoms. Immunohistochemical evaluation finds that most rectal GIST tumors are CD117 (KIT) positive, and are sometimes CD34, platelet-derived growth factor receptor alpha (PDGFRA), smooth muscle actin, S-100, or vimentin positive. The National Institutes of Health (NIH) classifies rectal GIST as very-low risk, low risk, intermediate risk, or high risk, and the frequencies have been estimated as 0-23.8% for very-low risk, 0-45% for low risk, 0-34% for intermediate risk, and 21-100% for high risk tumors. The first-line treatment for localized GIST is curative resection, but is difficult in rectal GIST because of anatomical characteristics such as the deep, narrow pelvis and proximity to the sphincter muscle or other organs. Several studies noted the efficacy of the minimally invasive surgery, such as trans-anal, trans-sacral, trans-vaginal resection, or laparoscopic resection. The appropriate surgical procedure should be selected depending on the case. Imatinib mesylate (IM) is indicated as first-line treatment of metastatic or unresectable GIST, and clinical outcomes are correlated with KIT mutation genotype. However, the KIT mutation genotypes in rectal GIST are not well known. In this review, as in other GISTs, a large proportion (59-100%) of rectal GISTs carry exon 11 mutations. Although curative resection is indicated for localized rectal GIST, a high rate of local recurrence is a problem. Multimodal therapy including perioperative IM may improve postoperative outcomes, contributing to anus-preserving surgery. Moreover, KIT mutation analysis before IM treatment is important. This review summarizes current treatment strategies for rectal GIST.

[A radiomics-based model for differentiation between benign and malignant gastrointestinal stromal tumors]

OBJECTIVE

To establish a model for discrimination between benign and malignant gastrointestinal stromal tumors (GIST) by analyzing the texture features extracted from computed tomography (CT) images.

METHODS

The CT datasets were collected from 110 patients with GIST (including 80 as the training cohort and 30 as the validation cohort). Feature set reduction was executed with the 0.632 + bootstrap method in the initial feature set followed by stepwise forward feature selection in the feature subset, and the classification model was generated by logistic regression.

RESULTS

The 6-texture-featurebased classification model successfully discriminated between benign and malignant GIST in both the training and validation cohorts with AUCs of 0.93 and 0.91, sensitivity of 0.88 and 0.87, specificity of 0.85 and 0.86, and accuracy of 0.87 and 0.86 in the two cohorts, respectively.

CONCLUSIONS

This classification model established by radiomics analysis is capable of discrimination between benign and malignant GIST to provide assistance in preoperative diagnosis of GIST.

Gastrointestinal Stromal Tumors (GISTs): From Science to Targeted Therapy

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. GISTs represent a distinct category of tumors characterized by oncogenic mutations of the KIT receptor tyrosine kinase in a majority of patients. KIT is useful not only for the diagnosis but also for targeted therapy of this disease. Imatinib, a tyrosine kinase inhibitor, is widely used in advanced and metastatic GISTs. This agent revolutionized the treatment strategy of advanced disease and is being tested in the neoadjuvant and adjuvant settings with encouraging results. New therapeutic agents like sunitinib have now been approved, enriching the treatment scenario for imatinib-resistant GISTs. The present review reports on the peculiar characteristics of this disease through its biology and molecular patterns, focusing on the predictive value of KIT mutations and their correlation with clinical outcome as well as on the activity of and resistance to approved targeted drugs.

Rare gastrointestinal stromal tumors (GIST): omentum and retroperitoneum

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasms that arise in the gastrointestinal tract and rarely elsewhere in the abdomen. GISTs that develop outside the digestive tract are called extra-GISTs (EGISTs). The incidence of EGISTs is reported to be approximately 10% of all GISTs, and the median age is younger than that of conventional GISTs. EGISTs have similar histology and immunohistochemical features as conventional GISTs, with the majority of them in the omentum and mesentery. Most GISTs harbor a kinase-activating mutation in either KIT or PDGFRA. For EGISTs, the incidence of this type of mutation is 40-50%, which is somewhat lower than for conventional GISTs. EGISTs may have a worse prognosis compared with conventional GISTs with high mitotic indices, large size, and distant metastasis including lymph node involvement. In large abdominal tumors, the visceral origin is almost impossible to discern.

Clinicopathological and Prognostic Features of Surgical Management in Duodenal Gastrointestinal Stromal Tumors

BACKGROUND AND OBJECTIVES

The rarity of duodenal gastrointestinal stromal tumors (DGIST) led to only limited data being available on their management and prognosis. We retrospectively analyzed the clinicopathological features, surgical treatments, adjuvant therapy, and prognosis of DGIST.

METHODS

Sixty-one patients were identified at diagnosis of primary DGIST from February 2005 to December 2015. One hundred twenty six patients with small intestinal gastrointestinal stromal tutors (GIST) were selected as control groups. Survival analyses were calculated using the Kaplan-Meier method.

RESULTS

Three- and five-year recurrence/metastasis-free survival rates of patients with DGIST were similar to those of patients with small intestinal GIST (p > 0.05 for all). Out of 61 cases with DGIST, 45 patients were treated with Limited Resection (LR). Sixteen patients were treated with Pancreaticoduodenectomy (PD). The 3- and 5-year recurrence/metastasis-free survival rates of the PD group and LR group were of no significant difference (p > 0.05 for all). Univariate analysis indicated that factors including surgical approaches, mitotic count, size, and risk grades were significantly associated with recurrence/metastasis-free survival (log-rank test, p < 0.05). Multivariate analysis demonstrated that the mitotic count was independently correlated with a worse recurrence/metastasis-free survival.

CONCLUSIONS

Patients with radical resected DGIST had a favourable prognosis, which is similar to that of small intestinal GIST. Both LR and PD were optimal choices for treating DGIST.

Rare case of primary leiomyosarcoma of sigmoid mesocolon

We experienced a rare case of primary leiomyosarcoma of sigmoid mesentery. A 45-year-old woman was presented to us with left iliac fossa mass and discomfort for 4-month duration. CT scan of abdomen and pelvis revealed a huge mass 14 cm×14 cm×16 cm occupying left iliac fossa mimicked having a large left ovarian carcinoma. She was subsequently planned for elective total abdominal hysterectomy and bilateral salpingo-oophorectomy by gynaecology team. During laparotomy, a huge mass was revealed arising from sigmoid mesentery invaded to the left lower ureter. Curative resection was done and pathological findings show the tumour being leiomyosarcoma with immunohistochemistry tests on caldesmon, desmin, smooth muscle actin and CD34 reagent all positive. Clinicopathological and literature review of this rare primary leiomyosarcoma of mesocolon was discussed in our case presentation.

What is New in Gastrointestinal Stromal Tumor?

The classification "gastrointestinal stromal tumor" (GIST) became commonplace in the 1990s and since that time various advances have characterized the GIST lineage of origin, tyrosine kinase mutations, and mechanisms of response and resistance to targeted therapies. In addition to tyrosine kinase mutations and their constitutive activation of downstream signaling pathways, GISTs acquire a sequence of chromosomal aberrations. These include deletions of chromosomes 14q, 22q, 1p, and 15q, which harbor putative tumor suppressor genes required for stepwise progression from microscopic, preclinical forms of GIST (microGIST) to clinically relevant tumors with malignant potential. Recent advances extend our understanding of GIST biology beyond that of the oncogenic KIT/PDGFRA tyrosine kinases and beyond mechanisms of KIT/PDGFRA-inhibitor treatment response and resistance. These advances have characterized ETV1 as an essential interstitial cell of Cajal-GIST transcription factor in oncogenic KIT signaling pathways, and have characterized the biologically distinct subgroup of succinate dehydrogenase deficient GIST, which are particularly common in young adults. Also, recent discoveries of MAX and dystrophin genomic inactivation have expanded our understanding of GIST development and progression, showing that MAX inactivation is an early event fostering cell cycle activity, whereas dystrophin inactivation promotes invasion and metastasis.

Extragastrointestinal stromal tumour of the lesser omentum: A case report and literature review

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EGISTs are very rare mesenchymal tumours which originate from cells outside the gastrointestinal tract and tend to have an aggressive biological behaviour.

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There have been only a few previous reports of EGISTs arising in the lesser omentum.

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Complete surgical resection is the most effective treatment associated with the use of imatinib in the presence of adverse prognostic factors.

Introduction

Extragastrointestinal stromal tumours (EGISTs) are very uncommon compared to their gastrointestinal counterparts. Most of them originate from the intestinal mesentery and the omentum.

Case report

A 70 year-old Caucasian woman presented with a bulky abdominal mass which on laparotomy was found to originate from the lesser omentum and was completely resected. Histological examination revealed spindle cells with severe pleomorphism and high mitotic activity. Immunohistochemically, the tumour cells showed strong positivity for c-kit (CD117), DOG-1 and human haematopoietic progenitor cell antigen (CD34). An exon 11 deleterious mutation was identified and thus regular dosing of 400 mg imatinib mesylate was initiated.

Discussion

There have been only a few previous reports of EGISTs arising in the lesser omentum. Although EGISTs seem to have morphological and immunohistochemical similarities with GISTs, their pathogenesis, incidence, genetic background and prognosis are not completely known because they are extremely rare. It is strongly believed that such tumours originate from cells, which have similar pathological characteristics and biological behaviour as the intestinal cells of Cajal. In most series of EGISTs, a female predominance, a greater size and a higher mitotic index than GISTs were observed.

Conclusion

EGISTs are very rare mesenchymal tumours which originate from cells outside the gastrointestinal tract and tend to have a more aggressive biological behaviour than their GI counterparts. Complete surgical resection is the most effective treatment associated with the use of imatinib in the presence of adverse prognostic factors. In any case a strict follow-up is necessary due to high recurrence rates.

A Rare Case of Mesenteric Gastrointestinal Stromal Tumor Presenting as Acute Abdomen

Gastrointestinal stromal tumours (GIST) are rare tumours arising from mesenchyme of gastrointestinal tract and overexpress C-kit protein. Mainly seen in stomach and small bowel. Mesenteric GIST are rarely reported as they constitute less than 1% of total GIST. We here report such a rare case of GIST arising from mesentery of small bowel and presenting as acute abdomen. Good surgical clearance ensures good survival whereas incomplete resection results in a high incidence of recurrences with distant metastasis.