Extragastrointestinal Stromal Tumors Research Articles

Pancreatic Extra-Gastrointestinal Stromal Tumour Presenting as an Intra-Abdominal Abscess: A Case Report and Literature Review

Introduction: Pancreaticoduodenectomy is one of the most frequently performed operations for pancreatic lesions around the world. Some pancreatic malignancies are particularly rare and difficult to diagnose preoperatively. Gastrointestinal stromal tumour is a common mesenchymal neoplasm of the gastrointestinal tract rarely found outside its boundaries. We report a case of a patient who presented to our hospital with a large intra-abdominal abscess with a unique post operative pancreatic extra-gastrointestinal stromal tumour (EGIST) as the final pathology. Presentation of case: We report a -32 year- old female who was admitted through the emergency department complaining of epigastric pain of one-week duration associated with spikes of fever and anorexia. The performed investigations manifest a large mass with infected central necrosis. The patient was managed initially with percutaneous drainage and intravenous antibiotics. Two weeks later the patient underwent whipple’s procedure and was discharged home uneventfully. The final histological report came as pancreatic extra-gastrointestinal stromal tumour. Discussion: Primary EGISTs outside the gastrointestinal tract are quite rare and account for up to 5%. It can originate from any mesenchymal organ. Primary pancreatic EGIST is a distinctly and extremely rare tumour. only few cases have been reported in the literature. Conclusion: Despite the rarity of this type of malignancy involving the pancreas, all hepatobiliary surgeons should keep it in mind as a possible pathology. Much effort must be done to make the diagnosis preoperatively apart from emergency presentation. Large pancreatic tumours with necrosis or cystic degeneration should ignite the suspicion of EGIST.Tabled 1Histology reportCD117+CD34+Desmin-Synaptophysin-Chromogranin-Lymph N14 reactive Open table in a new tab

Histomorphological Spectrum and Immunohistochemical Features of Gastrointestinal Stromal Tumour: A Series of Eight Cases

Gastrointestinal Stromal Tumours (GISTs) are rare tumours of the Gastrointestinal Tract (GIT), consisting of <1% of all primary GIT neoplasms. Recent studies show an increased incidence, which may be due to improved diagnostic facilities. In contrast to the literature’s judgement and the findings of many Western research, which state that the stomach is the most common place, it was observed that the small intestine was more common. Consequently, the goal of this case series was to characterise the clinicopathological, histomorphological, and immunohistochemical spectrum of GISTs as well as their risk categorisation in accordance with the modified Miettinen and Lasota’s algorithm. Eight patients with GISTs diagnosed between January 2017 and December 2020 at tertiary care centre of Gujarat, India are presented in this case series. There was one young woman among the patients, others were middle or old age male or female and had a median age of 58.5 years. The most typical presentation was abdominal pain, albeit in one instance it was an unexpected discovery. One example of extra Extra GISTs (EGIST), where there were several retro and intraperitoneal masses, and one small intestinal GIST each had lymphoma as the tentative clinical diagnosis. Predominant spindle cell morphology was observed in contrast to other studies. Even if molecular studies are not available in resource-limited countries, the basic Immunohistochemistry (IHC) panel is the most useful in the final diagnosis. Risk stratification criteria are helpful for prognostication and further management with the use of appropriate targeted therapies.

Clinical Features of Extragastrointestinal Stromal Tumor Compared with Gastrointestinal Stromal Tumor: A Retrospective, Multicenter, Real-World Study.

Objective This study aimed to compare the tumor characteristics and long-term outcomes between EGIST and GIST. The confounding function was applied to improve the result credibility in the case of small sample size. Design, Setting, and Participants. This cohort study enrolled 55 patients with EGIST who underwent surgery and were selected from four high-volume hospitals in China and 221 GIST patients who were collected from one of the four hospitals between January 2006 and September 2017. We used propensity score matching (PSM) and subgroup analysis to compare EGIST with GIST in terms of prognosis. The confounding function was used for sensitivity analysis to reduce unmeasured confounding. Results We matched 43 patients in each of the GIST and EGIST groups by PSM. We compared EGIST data with GIST data to explore the prognostic factors between them. In the multivariate Cox regression model, tumor location of EGIST was negatively correlated with overall survival (after PSM: HR, 4.32; 95% CI, 1.22–15.26) or disease-free survival (after PSM: HR, 9.79; 95% CI, 2.22–43.31), which was also intuitively shown in the Kaplan–Meier survival curves (all P values < 0.05). In the subgroup analysis, EGIST with high risk factors had a worse prognosis than GIST. In unmeasured confounding analysis, the overall curve tends to show all combinations of c(0) of c(1) up to 2.0, none of which would bring the corrected relative risk to 1 for OS and DFS. Conclusions and Relevance. EGIST was associated with worse prognosis compared with GIST patients, particularly in EGIST patients with high risk factors, while there was a similar prognosis without those high risk factors.

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.

S3071 Humongous Refractory Gastrointestinal Stromal Tumor With an Unusual Mutation

Introduction: Gastrointestinal stromal tumors (GIST) are rare mesenchymal neoplasms that arise from any part of the gastrointestinal tract. Its incidence varies between 7 and 8 percent per million inhabitants per year with a and median age of diagnosis of 63 years old. Extragastrointestinal stromal tumors make up less than 5 percent of cases, and most cases are secondary to advanced disease. Here we present a case of a catastrophic progression GIST with few or no previously documented mutation refractory to available therapies. Case Description/Methods: A 46-year-old man with a history of Omental GIST in remission after 5 years of treatment after imatinib attended the emergency room due to abdominal pain. Symptoms began suddenly with constipation, early satiety, and changes in stool size. Physical examination with a distended abdomen and positive liquid wave. laboratory analysis with 9.4 g / dL of hemoglobin. Abdominal CT reveals a large mesenteric mass measuring 15.6 x 10.2 x 24.6 cm in the lower abdomen extending into the pelvic region. Biopsy of the lesion reported a high-risk recurrent GIST with high Ki67 proliferation and a very high mitotic range. High-throughput and pathological sequences reported negative mutations in C-kit, CD117 and CD34, CDX-2, Betacatenin, LCA, CD3, CD20, Vimentin, and EXON 13,14 positive. Treatment was started with unanswered imatinib and then switched to sunitinib with disease progression and worsening disease burden. Treatment with regorafenib was started but, unfortunately, aggressive progression of the disease with a mass effect that affects multiple organs, so the patient did not tolerate the therapy. During the prolonged stay, the patient was complicated by spontaneous bacterial peritonitis, massive pulmonary embolism, and multi-organ failure, resulting in his death. Discussion: Our patient presented mutations in exon 13 and 14 rarely described in the literature that makes up less than 1% of GIST cases and does not have definitive treatment. It is presumed that the mutation in exon 13 responds to imatinib although in our patient it did not slow it down. progression of the disease. KIT-negative GISTs that progress during or after treatment with sunitinib and imatinib can be challenging for pathologists and clinicians. The implementation of next-generation gene sequences in clinical practice provides a major step forward in the implementation of target therapies and further studies. Tumor markers need to be developed for early detection, monitoring, and treatment.

P-93 The characteristics and prognosis of extragastrointestinal stromal tumors: A single center retrospective analysis of 31 patients

Extragastrointestinal stromal tumors (EGISTs) are a special type of gastrointestinal stromal tumors (GISTs) that have similar pathologic characteristics but without any connection to the alimentary tract. Although EGISTs have been reported seemingly with more malignant behaviors by previous publications, the understanding of EGISTs still remains to be improved for its extremely rare prevalence. The aim of this study was to investigate the basic features of EGISTs and analyze the factors related to prognosis.

P-251 Multidisciplinary challenge for the oncologist and surgeon: Gastrointestinal stromal tumors. Follow-up of a tertiary surgical department

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors in gastrointestinal system with most found in stomach. With the characteristic of being mostly c-KIT positive (CD117) as a mutation carrier, genetics is a part of the management of GIST, helping both the surgeon and the oncologist. The diagnosis and the definition of the characteristics of tumor will help to define the response to treatment procedures, which is fundamental for oncologists and surgeons to create an algorithm for their patients. The follow-up should be done both with oncologists and surgeons in order to define early recurrences and metastasis. This study is based on the follow-up of GIST patients operated in a tertiary general surgery department. 43 patients have been operated on between January 2017-December 2018. Routine preoperative diagnostic findings and postoperative pathological evaluations are identified and noted. In our hospital, routine management of GIST is as follows: In case of high grade GISTs, postoperative adjuvant imatinib therapy is routinely given for three years, and if there is metastasis or locally unresectable tumor, neoadjuvant imatinib treatment is given for shrinking the primary tumor and curing the systemic disease before the surgery. As the primary and golden treatment of GIST is surgery, surgery is always an option for even metastatic disease. Of 43 patients, 23 patients had a mitosis rate under 5/50, whereas 5 patients had a mitosis rate between 5/50 – 10/50, and 15 patients had a mitosis rate over 10/50. According to the size of the tumor, 3 patients had a single tumor under 2 cm. All of these three patients had lesions in the prepiloric area, and got operated with the symptoms of gastric outlet syndrome. 17 patients had a tumor between 2-5 cm, whereas 14 patients had a tumor between 5-10 cm. 9 patients had GIST tumors over 10 cm in diameter. Interestingly, all patients with liver metastasis had liver lesions over 10 cm. One patient with a tumor bigger than 10 cm had an extragastrointestinal stromal tumor, arising from the mesentery. The pathological results of the specimens were as follows: 29 spindle cell histologic subtype, 3 epitheloid cell subtype, and 11 mixed cell subtype. The focal necrosis was present in 14 patients. From 43 patients, three patients got reoperated. The first patient was reoperated at the fifth month postoperatively because of mechanical obstruction. The second patient got reoperated at the ninth month postoperatively because of incisional hernia. The third reoperated patient was reoperated because of the first pathological specimen was found out to be surgical borders millimetrically positive. The reoperation rate for our patients in three years of follow up was 6.97%. All reoperated patients had a pathological finding of spindle-cell type of morphology, with mitosis rates over 10/50. There needs to be more studies based on reoperation rates after GIST surgeries, but this study evaluated that complications after GIST surgery should be followed both by the oncologist and the surgeon.

C-kit-negative Extragastrointestinal Stromal Tumor Originating in the Mesentery Misdiagnosed as an Ovarian Tumor before Surgery

Gastrointestinal stromal tumors (GISTs) are rare digestive system malignancies with extragastrointestinal stromal tumors (EGISTs) being even less. Diagnosing GISTs usually requires the identification of c-kit (CD117) expression by immunohistochemical staining. A 53-year-old woman complaining of dyspepsia was referred for the evaluation of a 1.5-cm extrinsic compression at the greater curvature of the proximal antrum. EUS revealed a multiseptated mass with positive Doppler findings. Abdominal CT showed that she harbored a large, 20-cm mass in her abdominal cavity, most likely arising from the right ovary. Surgery revealed a hypervascular tumor arising from the mesentery and attached to the gastric lesser curvature. Pathological examination revealed negativity for c-kit, but positivity for the protein “Discovered on GIST-1” (DOG1), confirming the EGIST diagnosis. Herein, we report this rare case of a c-kit-negative EGIST originating in the mesentery, which was diagnosed based on staining for DOG1.

The Immune Response in Gastrointestinal Stromal Tumors

Background: Gastrointestinal stromal tumors (GISTs) are the most frequent tumors with mesenchymal origin at the level of the digestive tract. Assessment of intratumoral immune cells can provide valuable prognostic information and may contribute to the development of targeted immune therapies for selected cases. Here in we evaluated the inflammatory infiltrate in gastrointestinal stromal tumors, the ratios between cytotoxic and helper T cells and their prognostic significance. Methods: We retrospectively analysed 25 cases of GISTs and extragastrointestinal stromal tumors (EGISTs). Immunohistochemical testing for CD3, CD4, CD8, CD20 and CD68 was performed to emphasize the immune cells. Inflammatory cells were quantified with the help of ImageJ software. Statistical analysis was performed to search for correlation between the immune response and clinical-pathological and prognostic variables. Results: GISTs were in all cases infiltrated with immune cells in variable amount. The pattern of distribution was diffuse or in aggregates, most frequent around blood vessels. Gastric tumors had the largest amount of inflammatory infiltrate and EGISTs the lowest. The dominant intratumoral immune cells were represented by lymphocytes, with fewer plasma cells, histiocytes, eosinophils, neutrophils and mast cells. CD3+ lymphocytes were the most common subtype. In 9 cases the CD8+/CD4+ ratio was subunitary. An increased number of histiocytes were associated with a high risk of disease progression. No other correlation between immune cells and other prognostic factors were established. Conclusion: Gastrointestinal stromal tumors represent the site of complex interactions between various types of immune cells and neoplastic cells. Accumulation of CD68+ cells correlates with high risk GISTs. Our paper provides an overview on the inflammation in this tumor type and further studies are necessary for more comprehensive results.

Primary extra gastrointestinal stromal tumors of the abdomen.

OBJECTIVE:In the present study, we aimed to evaluate the clinicopathological features and prognostic factors in extra-gastrointestinal stromal tumor (EGIST) cases, which are observed very rare, by examining the data the cases obtained in a single center.METHODS:Data of 14 EGIST cases who were operated by a general surgeon between January 2007 and May 2020 were obtained and analyzed.RESULTS:The median age was 47.5 (range: 34–87) years. A total of 135 patients were operated for GIST, and 14 (10.4%) of these patients were EGIST. The mean tumor diameter was 16.8±10.5 (range: 2.8–40) cm. The mitotic index was 5/50 high power field and below in seven (50%) cases. Twelve (85.7%) of the patients were in the high-risk group. The overall survival (OS) rate was 80%, and the 5-year survival rate was 88.9%. Mean OS was 78.5±50.7 months, 5-year OS and disease-free survival (DFS) were both 53.3±20.0 months, and overall DFS was 58.0±59.8 months. The mean OS and DFS durations were found to be significantly lower in women than men (p=0.006 for both comparisons). The mean OS was found to be significantly lower in patients over 60 years of age compared to those aged 60 and under (p=0.013).CONCLUSION:In the present study, it has been determined that the rare EGISTs are large in size and that the mitotic index is often low. In addition, it has been observed that the prognosis may be similar to other GISTs, however, may be worse in elderly patients and in women.

Gastrointestinal Stromal Tumors (GISTs) and Extragastrointestinal Stromal Tumors (E-GISTs) - A Review

GISTs (Gastrointestinal Stromal Tumors) are the most frequently encountered mesenchymal tumor of the gastrointestinal tract. Gastrointestinal stromal tumors have been recognized as a biologically distinctive tumor type, different from smooth muscle and neural tumors of the gastrointestinal tract (GIT). GISTs present 0.1%-3.0% of gastrointestinal malignant tumors. The goals in treating patients with GIST are to maximize the chance of cure, minimize recurrence. A multidisciplinary approach to patients with GISTs is necessary to optimize the timing of medical and surgical therapy as they have unpredictable behavior. Also long term follow up is essential for all patients, independent of their benign or malignant characteristics. This review highlight on clinical, diagnostic imaging, histopatholpgical, immunohistochemical ,new markers and management modalities for Gastrointestinal Stromal Tumors (GISTs) and Extragastrointestinal stromal tumors (E-GISTs).

Prevalence, diagnosis, and treatment of primary hepatic gastrointestinal stromal tumors.

Gastrointestinal stromal tumors (GIST), which is the most common mesenchymal tumor of the digestive tract, account for 1%-3% of gastrointestinal tumors. Primary stromal tumors outside the gastrointestinal tract are collectively referred to as extra GISTs, and stromal tumors in different regions often have different prognoses. A primary hepatic GIST is a rare tumor with an unknown origin, which may be related to interstitial Cajal-like cells. Although primary hepatic GIST has certain characteristics on imaging, it lacks specific symptoms and signs; thus, the final diagnosis depends on pathological and genetic evidence. This review summarizes all cases of primary hepatic GIST described in the literature and comprehensively analyzes the detailed clinical data of all patients. In terms of treatment, local resection alone or with adjuvant therapy was the prioritized choice to obtain better disease-free survival and longer survival time. For advanced unresectable cases, imatinib mesylate was applied as the first-line chemotherapy agent. Moreover, transcatheter arterial chemoembolization, radiofrequency ablation, and microwave ablation were shown to improve overall survival for selected patients. Liver transplantation was a final treatment option after resistance to chemotherapy developed.

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

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

S3032 Extra-Gastrointestinal Stromal Tumor (EGIST): An Unusual Case of Worsening Exertional Dyspnea

INTRODUCTION: Gastrointestinal stromal tumors (GISTs) are mesenchymal tumors of the gut. GISTs are rare, composing 0.1-3% of all gastrointestinal tumors. Exceedingly rare cases of GISTs have been identified outside of the GI tract and named extra-gastrointestinal stromal tumors (EGISTs). Here, we present a case of a large EGIST with multiple metastasis that initially presented with worsening exertional dyspnea. CASE DESCRIPTION/METHODS: An 83-year-old female with past medical history significant for hypertension and breast cancer status post lumpectomy and radiation therapy presented with worsening shortness of breath on exertion for 6 weeks. She also reported mild left upper quadrant abdominal pain, weakness, and decreased appetite. On physical exam, her abdomen was distended with splenomegaly noted. CTA of the chest shows right-sided pulmonary emboli without right ventricular strain and intra-abdominal ascites with a markedly enlarged spleen. US of lower extremities was positive for right femoral deep vein thrombosis. The patient was placed on heparin drip, which was later changed to Lovenox. Abdominal US shows multiple intrahepatic lesions and epigastric mass. CT of the abdomen and pelvis shows a large mass occupying a majority of the abdominal and pelvic cavities and multiple metastasis noted to liver and adrenal glands. Core biopsy of the abdominal mass showed high grade (Grade 2, x > 5 mitotic figures per 5 mm) GIST with necrosis. Tumor cells were positive for DOG1, CD117, and CD34. EGD revealed antral gastritis with biopsy positive for H. pylori. She was discharged and placed on Imatinib with repeat imaging after several months of Imatinib to evaluate for possible resection of disease. DISCUSSION: EGISTs are rare mesenchymal tumors that have been identified in the retroperitoneum and pelvis. GISTs result from activating mutations of proto-oncogenes c-KIT (CD117) or PDGFR-alpha. These activated proto-oncogenes increase tyrosine kinase receptor activity and result in stem cell proliferation. Roughly one third of GISTs have malignant potential and are prone to metastatic spread. GIST prognosis is multifactorial, depending on tumor size, mitotic potential, and metastatic invasion. Imatinib, a tyrosine kinase inhibitor, is the first-line therapy of metastatic GIST. In addition, surgical resection is the mainstay of therapy, especially in cases where the lesion is > 2 cm. In the 3 to 5 years post-treatment, close surveillance is warranted due to high risk of GIST recurrence.Figure 1.: Abdominal and Pelvic GIST on CT of the abdomen and pelvis.Figure 2.: Abdominal and Pelvic GIST on CT of the abdomen and pelvis.

S3029 Unexpected Diagnosis of Worsening Abdominal Distension

INTRODUCTION: Gastrointestinal stromal tumors (GISTs) constitute about 1% of primary gastrointestinal cancers. Primary omental GIST without gastrointestinal involvement (extra-gastrointestinal stromal tumor or EGIST) is extremely rare. We present a case of EGIST with peritoneal metastases and partial response to Imatinib. CASE DESCRIPTION/METHODS: A 68-year-old Caucasian male with a history of coronary artery disease and chronic obstructive lung disease presented with shortness of breath and progressively worsening abdominal distension for several months. Labs were significant for hemoglobin of 10.8 g/dL and positive fecal occult blood test. Computed tomography (CT) of the abdomen and pelvis revealed innumerable masses in the peritoneum and omentum (Figure 1), with no solid visceral abnormality. CT-guided core biopsy of an omental mass revealed cluster spindle cells diffusely positive for c-kit (CD117) (Figure 2) and CD34, with negative stains for cytokeratin 5/6, D2-40, calretinin, cytokeratin AE1/3, Melan-A, S-100, and actin, consistent with EGIST. Subsequent esophagogastroduodenoscopy and colonoscopy with biopsy did not reveal any neoplastic lesion. His symptoms dramatically improved with Imatinib. Follow-up CT scan 3 months later showed partial remission (Figure 3). DISCUSSION: Primary omental stromal tumors without GI tract involvement or attachment are exceedingly rare. Classic GISTs originate from the interstitial cells of Cajal (ICCs) or their stem cells. EGISTs share the same immunophenotype despite arising outside of GI tract, as the tumors either lose their original connection with GI tract or originate from ICC-like precursor cells dispersed during fetal development. The most common symptoms associated with omental stromal tumors are abdominal distension and pain. The tumors are often found as large masses as they tend not to cause obstruction and associated symptoms at earlier stages. CT is the preferred imaging modality for identification of the primary tumors and metastases. Endoscopy can be used to obtain additional information and biopsy. There are no established treatment guidelines for EGIST, and the guidelines developed for GIST are typically used for management of EGIST. Surgery is the primary treatment for localized disease. In our case, Imatinib was utilized due to numerous non-resectable masses, leading to partial remission. More studies are needed to better understand the pathophysiology and evaluate treatment options for EGIST.Figure 1.: Initial abdominal CT revealed extensive lymphadenopathy and multiple soft tissue masses in the peritoneum and omentum.Figure 2.: The biopsied mass was mostly made of cluster spindle cells with high cellularity and frequent mitotic activity, with diffusely positive stain for CD117/c-KIT, a key proto-oncogene activated in GISTs.Figure 3.: A repeat abdominal CT, in 3 months after the diagnosis, showed partial response to Imatinib.

An unusual presentation of an extragastrointestinal stromal tumour: a case report

BackgroundGastrointestinal stromal tumours (GISTs) account for most mesenchymal gastrointestinal tumours, which in turn represent 1% of all gastrointestinal cancers. They mainly affect older adults, with a slight male preponderance. These lesions can be found along the digestive tract and most frequently in the stomach. Extragastrointestinal stromal tumours (EGISTs) are even rarer lesions, with few cases or series reported.Case presentationA 51-year-old woman was referred to our hospital due to progressive abdominal volume increase. Evaluation by multidetector computed tomography (MDCT) revealed a large intraperitoneal mixed tumour with few solid components, measuring up to 30 cm and compressing the surrounding structures, thought to be an ovarian tumour. Diagnostic laparotomy showed that the lesion was adherent to the greater gastric curvature and the vesical peritoneum. The lesion was removed without complications.ConclusionsImaging plays an essential role in the diagnosis of large intraperitoneal tumours. MDCT is the preferred technique to stage and to follow-up EGISTs.

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

BackgroundGastrointestinal 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 presentationA 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.ConclusionWe 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.

Extra Gastrointestinal Stromal Tumor Pada Ovarium, Kasus Jarang

Objective : This article objective is to describe a woman with extra gastrointestinal stromal tumor (extra GIST) in ovary; Method : A case report and literature review; The author reports a woman 54 years old with complaints of swelling in the abdomen. Tumors suspected originate from ovary with an extension to abdominal wall. The patient had history of previous ovarian tumor surgery with pathological anatomy diagnosis was thecoma. Working diagnosis of the patient was residif ovarian malignancy and then suboptimal debulking was performed. Microscopically, ovarian tumors appear cellular and diffuse, partially arranged fascicles. Cells with rounded-spindle nuclei, mitosis ≥ 4 per 10 HPF. The conclusion was malignant thecoma which metastasizes to peritoneum and omentum. Differential diagnosis were GIST and leiomyosarcoma. Immunohistochemistry examination was performed with Calretinin and CD117 to rule out the differential diagnosis. Calretinin were negative and CD117 were strongly positively smeared. Based on the morphology and positive CD117 results, diagnosis was extra GIST of ovary.; Conclusion: Extra GIST in the ovary is an unusual location so that it can be misdiagnosed as a gynecological disorder. The differential diagnosis at this location is quite limited including thecoma, fibrothecoma and leiomyosarcoma.Keywords: extra gastrointestinal stromal tumor, ovary, thecoma

Extra Gastrointestinal Stromal Tumor Pada Ovarium, Kasus Jarang

Objective : This article objective is to describe a woman with extra gastrointestinal stromal tumor (extra GIST) in ovary; Method : A case report and literature review; The author reports a woman 54 years old with complaints of swelling in the abdomen. Tumors suspected originate from ovary with an extension to abdominal wall. The patient had history of previous ovarian tumor surgery with pathological anatomy diagnosis was thecoma. Working diagnosis of the patient was residif ovarian malignancy and then suboptimal debulking was performed. Microscopically, ovarian tumors appear cellular and diffuse, partially arranged fascicles. Cells with rounded-spindle nuclei, mitosis ≥ 4 per 10 HPF. The conclusion was malignant thecoma which metastasizes to peritoneum and omentum. Differential diagnosis were GIST and leiomyosarcoma. Immunohistochemistry examination was performed with Calretinin and CD117 to rule out the differential diagnosis. Calretinin were negative and CD117 were strongly positively smeared. Based on the morphology and positive CD117 results, diagnosis was extra GIST of ovary.; Conclusion: Extra GIST in the ovary is an unusual location so that it can be misdiagnosed as a gynecological disorder. The differential diagnosis at this location is quite limited including thecoma, fibrothecoma and leiomyosarcoma.Keywords: extra gastrointestinal stromal tumor, ovary, thecoma

Abdominal wall mass suspected of endometriosis: clinical and pathologic features.

ObjectiveTo evaluate the clinical and pathological characteristics of lower anterior abdominal wall masses suspicious for endometriosis.MethodsA retrospective review of 38 patients who underwent surgery for a lower anterior abdominal wall mass suspicious for endometriosis was performed. Those with skin and intraperitoneal masses, lipomas, hernias, and metastatic malignant masses were excluded. Patient age, body mass index, delivery history, dysmenorrhea, and mass size and location were analyzed.ResultsThirty-seven (97.3%) patients had a relevant surgical history, including 35 (92.1%) with a history of cesarean section (C/S). Among the three patients with no history of C/S, 1 underwent total abdominal and another total laparoscopic hysterectomy, and 1 had no previous surgical history. The mean (±standard deviation) size of the abdominal masses was 3.2±1.2 cm. One patient developed a recurrent mass after excision of abdominal wall endometriosis. Trocar site endometrioma was found in one patient following total laparoscopic hysterectomy. According to the final pathology reports, endometriosis was found in 35 (92.1%) of patients. The remaining 3 patients (7.9%) had malignancy: adenocarcinoma, squamous cell carcinoma, and extra-gastrointestinal stromal tumor. Before surgery, only 3 patients (7.9%) underwent fine-needle aspiration biopsy of the masses, which were all postoperatively confirmed to be pathologically benign.ConclusionAlthough most abdominal wall masses in the present sample were endometriosis occurring at the scar site from a previous operation, 7.9% of patients ultimately exhibited malignancy. Therefore, all patients with suspected anterior wall endometriosis should undergo preoperative biopsy to identify the few that will have an alternative diagnosis.