Gastrointestinal stromal tumors: diagnostic challenges and practical approach to differential diagnosis

Hybrid surgical approach excision of gastrointestinal stromal tumor (GIST): A case report of GIST at an unusual location and review of the literature

Gastrointestinal stromal tumors are the most common malignant subepithelial lesions involving the gastrointestinal tract. Surgical techniques have been the mainstay of treatment, however, in recent times hybrid surgeries are being introduced yielding better clinical outcomes.

Mesenchymal neoplasms of the tubular gut and adjacent structures: experience with EUS-guided fine-needle aspiration cytopathology

INTRODUCTION

Unlike epithelial malignancies, mesenchymal neoplasms arising within the tubular gut are less often encountered in endoscopic ultrasound-guided (EUS) fine-needle aspiration biopsies (FNABs). Nonetheless, preoperative diagnosis of such neoplasms has important therapeutic and prognostic value. We report our experience with this category of neoplasms from the past decade.

MATERIALS AND METHODS

We performed a 10-year retrospective search at our respective institutions to identify EUS-guided FNAB cases of mesenchymal neoplasms arising from the tubular gut wall and closely adjacent structures. Cytopathologic diagnoses were compared to corresponding surgical pathology (SP) when available. Cases with either no confirmatory cell block (CB) immunohistochemical (IHC) staining, or no SP were excluded.

RESULTS

Two-hundred eighty-two cases (M:F = 1:1; age range: 25-94 years, mean age = 60 years) of EUS-guided FNAB from the tubular gut met our criteria. Onsite adequacy was performed on nearly all cases. Case numbers: 209 gastrointestinal stromal tumors (GIST), 58 smooth muscle neoplasms, and 15 miscellaneous neoplasms. Of these, 188 (67%) had SP follow-up. We found that 258 (91%) aspirates had a correct specific diagnosis, 3 (1%) were nondiagnostic, 18 (6%) had indeterminate diagnoses, and 3 (1%) had incorrect diagnoses (2 leiomyosarcomas mistaken as leiomyoma, and 1 fibrosclerotic lesion mistaken as inflammatory pseudotumor). Of 94 cases with no SP, all had a specific cytologic diagnosis based on confirmatory IHC staining from the CB including 61 GISTs, 29 smooth muscle neoplasms, and 4 miscellaneous tumors.

CONCLUSION

This study endorses the clinical utility of EUS-guided FNAB in the diagnosis of tubular gut mesenchymal neoplasms. A definitive and accurate diagnosis is possible in over 90% of cases, chiefly when cytomorphology is coupled with optimal cellularity and IHC from a concurrent CB. EUS-guided FNAB diagnosis of mesenchymal tubular gut neoplasms may play an important role in determining neoadjuvant therapy as targeted therapy evolves.

Transanal Endoscopic Microsurgery for Patients with Rare Rectal Tumors

BACKGROUND

Transanal endoscopic microsurgery (TEM) has been accepted worldwide for the treatment of local rectal lesions. Rare rectal tumors consist of several different types of malignant or benign tumors. Surgical management is considered to be the only curative option. The aim of this study is to investigate the role of TEM in the treatment of rare rectal tumors.

MATERIALS AND METHODS

A total of 147 patients with rare rectal tumors underwent TEM in our center from April 2006 to May 2017. Clinical data were collected and a retrospective accurate database was constructed. Demographic characteristics, operative details, tumor details, complications, and follow-up data were analyzed.

RESULTS

Seventy-eight patients were male. Mean tumor diameter was 1.2 ± 0.7 cm and mean distance from the anal verge was 6.6 ± 2.3 cm. Full-thickness and complete resection with negative margins was achieved in all patients. Complications occurred in 3 patients during surgery and in 20 patients after surgery. Histopathologic results were neuroendocrine tumors in 104 patients; gastrointestinal stromal tumors in 35; melanoma, lymphoma, and leiomyoma each in 2; lipoma, and squamous carcinoma each in 1. One hundred thirty-five patients were followed up for 49.3 ± 33.2 months. Two patients died, 1 had local recurrence and 1 had a rectovaginal fistula 1 month after surgery. No local recurrence or metastasis, or fecal incontinence was observed in the remaining patients.

CONCLUSION

TEM is an optimal treatment option for selected rare rectal tumors. The complication rate is low and the therapeutic effect is satisfactory.

A Case of Malignant Gastrointestinal Stromal Tumor Initially Misdiagnosed as Malignant B-Cell Lymphoma

Errors that occur in anatomic pathology influence the treatment strategy of patients with malignancy. There are four general types of error with three subtypes in the category of defective interpretation. The first subtype is a false-negative diagnosis or undercall of the extent or severity of the lesion, the second is a false-positive diagnosis, and the third is misclassification. We herein report a 65-year-old female patient with malignant gastrointestinal stromal tumor that was diagnosed after reevaluation of the lesion at our hospital – and treated with proximal gastrectomy – after initial diagnosis as malignant B-cell lymphoma on esophagogastroduodenoscopy biopsy of a small gastric fundic mass and subsequent treatment with six cycles of CHOP chemotherapy with aggravation of the mass at another hospital.

Meckel's diverticulum complicated with gastro-intestinal stromal tumor: Case report

INTRODUCTION

Meckel's diverticulum is a common congenital anomaly, mostly asymptomatic. Tumors may arise rarely in these diverticulae. We claim presenting a new problem to the medical staff in Egypt.

CASE PRESENTATION

We report a case of a 49year old male patient who attended our center with pelvic mass insinuated between the bladder and the rectum. On exploration the mass was found arising at the tip of a Meckel's diverticulum, Gastro-intestinal stromal tumor (GIST) was confirmed by pathology.

DISCUSSION

In review of recently published cases most of these tumors were presented with vague abdominal pain as in our case. Tumors were treated by resection with or without adjuvant Imatinib.

CONCLUSION

Surgeons and oncologists should bear in mind this rare diagnosis and know how to treat it.

Duodenal gastrointestinal stromal tumor: From clinicopathological features to surgical outcomes

Duodenal gastrointestinal tumors represent an extremely rare subset of stromal tumors arising from interstitial cells of Cajal. In the last 30 years the comprehension of the pathophysiology and natural history of this previously misunderstood clinical entity, in association with developments in endoscopy, imaging technology, and immunohistochemistry has resulted in novel diagnostic and treatment approaches. This is a comprehensive review of the current data of the literature on the various aspects of the diagnosis and treatment of these tumors. The duodenum is the less commonly involved site for these tumors in the digestive tract. Endoscopy and computed tomography can usually establish the diagnosis, confirmed by immunohistochemical staining and occasionally molecular genetic analysis. Endoscopic ultrasound with fine needle aspiration has been recently found to be the gold diagnostic standard with high sensitivity and specificity rates, diagnosing GIST in up to 80% of patients. Due to the complex anatomy of the pancreatico-duodenal region optimal therapeutic strategy of duodenal GISTs are challenging. Nevertheless surgical resection with microscopically clear resection margins seems to be the only potentially curative treatment for non-metastatic primary GISTs of the duodenum. Imatinib mesylate plays a key role in the management of GISTs both as neoadjuvant therapy and in patients with recurrent and metastatic disease. Meanwhile, the advances in the comprehension of the pathophysiology and natural history of this previously misunderstood clinical entity as well as the treatment of these tumors may render feasible, in the near future, the advent of newer and more effective treatment options.

Endoscopic versus open resection for small gastric gastrointestinal stromal tumors: safety and outcomes

Endoscopic resection has been performed to treat small gastric neoplasms. However, this technique for small gastric gastrointestinal stromal tumors (GISTs) remains controversial. This study aims to compare the safety and surgical outcomes of endoscopic versus open resection of small gastric GISTs.The medical records of 54 consecutive gastric GISTs patients with tumor size of ≤2 cm, who were surgically treated with endoscopic resection (endoscopic group) or open surgery (laparotomy group) in a single institution from March 2010 to June 2014, were retrospectively analyzed. The clinical and tumor characteristics, surgical safety, and tumor-related outcomes were evaluated.Of 54 patients, 32 and 22 patients underwent endoscopic resection and laparotomy, respectively. Patients who underwent endoscopic resection yielded a significantly shorter hospital stay compared with patients who underwent laparotomy (P < 0.001). Compared with patients in the endoscopic group, patients in the laparotomy group had more intraoperative blood loss (P < 0.001), had longer nasogastric tube retention (P < 0.001), and required longer operative time (P < 0.001). More laparotomy patients required postoperative analgesic drugs than those in the endoscopic group (n = 9 vs 4; P = 0.016). Gastric perforation occurred in 1 case during operation in the endoscopic group. Patients who underwent these 2 procedures did not differ with respect to tumor size (P = 0.168), perioperative transfusion (P = 1.000), reoperation (P = 1.000), early satiety (P = 0.560), and postoperative bleeding (P = 1.000). With a median follow-up time of 34.5 months, 1 high-risk patient in each group experienced tumor recurrence/metastasis postoperatively.The endoscopic procedure allows safe resection with good surgical outcomes for small gastric GISTs compared with laparotomy. Moreover, larger randomized controlled trials are warranted to confirm endoscopic application for small gastric GISTs.

Primary gastrointestinal stromal tumors: Current advances in diagnostic biomarkers, prognostic factors and management of its duodenal location

Gastrointestinal stromal tumors (GIST) constitute 1-3% of all gastrointestinal malignancies and is the most common mesenchymal tumor of the gastrointestinal tract. Although GIST were first described in the literature in the year 1941, important advances of kit mutation and tyrosine kinase inhibitors were not made to understand and manage GIST until the last decade. Here current advances in research of possible cellular origin, diagnostic biomarkers and prognostic factors of primary GIST are reviewed, and the management of primary duodenal GIST is focused on due to its specific location. It is possible that personalized assessment and therapy will turn out to be another milestone for primary GIST.

Gastrointestinal stromal tumor

Gastrointestinal stromal tumor has received a lot of attention over the last 10 years due to its unique biologic behavior, clinicopathological features, molecular mechanisms, and treatment implications. GIST is the most common mesenchymal neoplasm in the gastrointestinal tract and has emerged from a poorly understood and treatment resistant neoplasm to a well-defined tumor entity since the discovery of particular molecular abnormalities, KIT and PDGFRA gene mutations. The understanding of GIST biology at the molecular level promised the development of novel treatment modalities. Diagnosis of GIST depends on the integrity of histology, immunohistochemistry and molecular analysis. The risk assessment of the tumor behavior relies heavily on pathological evaluation and significantly impacts clinical management. In this review, historic review, epidemiology, pathogenesis and genetics, diagnosis, role of molecular analysis, prognostic factor and treatment strategies have been discussed.

Gastrointestinal stromal tumors (GISTs): an updated experience

BACKGROUND

Gastrointestinal stromal tumors (GISTs) are relatively common mesenchymal tumors of the digestive tract characterized by c-KIT mutations. This is a comprehensive review of the current data of the literature on the various aspects of the diagnosis and treatment of these tumors.

METHODS

The stomach is the most commonly involved site for these tumors in the digestive tract. Computed tomography and endoscopy can usually establish the diagnosis. The study of certain specific immunohistochemical markers may contribute to better characterization of these tumors.

RESULTS

Surgical resection of GISTs has been the most effective therapy. In addition, targeted therapy with tyrosine kinase inhibitors may reduce the development of recurrence or decrease the disease progression in patients with metastatic disease.

CONCLUSIONS

The introduction of tyrosine kinase inhibitors has resulted in significant improvement in the overall prognosis of these patients. Furthermore, preoperative imatinib can decrease tumor volume and is associated with complete surgical resection in locally advanced primary GISTs.

Gastrointestinal Stromal Tumors: A Guide to the Diagnosis

Gastrointestinal stromal tumors (GISTs) have emerged from being a poorly understood and therapeutically refractory sarcoma to a tumor whose biology has not only provided insight into a mechanism of oncogenesis but has also led to a rational basis for therapy. Most GISTs are characterized by KIT protein (CD117) expression and constitutive activating mutations in either the c-kit or platelet-derived growth factor receptor α genes. This information can now be obtained from routine formalin-fixed and paraffin-embedded tissue. Because the correct diagnosis is the key to successful treatment of this tumor, it is incumbent on the pathologist to be familiar with the various gross and histologic patterns shown by these tumors. GISTs range from small incidental stromal nodules to large cystic and solid tumor masses. GISTs show a variety of microscopic patterns and therefore several other tumors enter the differential diagnosis. Fortunately, with an understanding of GIST histology, and with the proper use of immunohistochemistry and molecular analysis, a correct diagnosis can usually be made. In addition to the correct diagnosis, several key attributes of the tumor need to be determined because they provide the basis for proper clinical management. This article summarizes the gross, microscopic, and molecular findings of GISTs, and discusses the differential diagnosis and key attributes of this interesting group of neoplasms.

The utility of discovered on gastrointestinal stromal tumor 1 (DOG1) antibody in surgical pathology-the GIST of it

DOG1 (discovered on GIST 1), known also as TMEM16A and ANO1, has emerged in recent years as a promising biomarker for gastrointestinal stromal tumors (GIST). It was originally discovered through microarray expression profiling analysis as gene that is highly expressed in GIST, and subsequent immunohistochemical studies have shown its use in its diagnosis. The results from several series have shown a high overall sensitivity and specificity for DOG1 in the detection of GISTs and about 6% of GISTs overall exhibiting a DOG1+/KIT-immunoprofile. DOG1 antibodies are more sensitive than KIT antibodies in detecting tumors of gastric origin, tumors with epithelioid morphology, and tumors harboring PDGFRA mutation. Furthermore, DOG1 immunoreactivity is rarely observed in other mesenchymal and nonmesenchymal tumor types. These results support the use of DOG1 as a diagnostic biomarker for GIST. When used in combination with KIT, this panel of diagnostic biomarkers can help pathologists and clinicians to identify more patients who may benefit from targeted therapies.

MicroRNA expression profile of gastrointestinal stromal tumors is distinguished by 14q loss and anatomic site

MicroRNAs are known to regulate gene expression. Although unique microRNA expression profiles have been reported in several tumors, little is known about microRNA expression profiles in GISTs. To evaluate the relationship between microRNA expression and clinicopathologic findings of GISTs, we analyzed the microRNA expression profiles of GISTs. We used fresh frozen tissues from 20 GISTs and analyzed KIT and PDGFRA mutations and chromosomal loss status. MicroRNA expression was analyzed using a microRNA chip containing 470 microRNAs. Using unsupervised hierarchical clustering analysis, we found four distinct microRNA expression patterns in our 20 GISTs. Six GISTs that did not have 14q loss formed a separate cluster. In the 14 GISTs with 14q loss, 5 small bowel GISTs formed a separate cluster and the remaining 9 GISTs could be divided into two groups according to frequent chromosomal losses and tumor risk. We found 73 microRNAs that were significantly down-regulated in the GISTs with 14q loss; 38 of these microRNAs are encoded on 14q. We also found many microRNAs that were down-regulated in small bowel and high-risk group GISTs. Most of the microRNAs down-regulated in the high-risk group and small bowel GISTs are known to be involved in tumor progression, specifically by stimulating mitogen-activated protein kinase (MAPK) and the cell cycle. The microRNA expression patterns of GISTs are closely related to the status of 14q loss, anatomic site, and tumor risk. These findings suggest that microRNA expression patterns can differentiate several subsets of GISTs.

Gastrointestinal stromal tumors: a review of the literature

Gastrointestinal stromal tumors are mesenchymal neoplasms with a spectrum of histologic appearances and biologic activity. The morphologic classification of these lesions has evolved over time, and molecular analysis has led to a better understanding of their nature. The histologic differential diagnosis for these lesions is broad and includes many spindle cell lesions of the gastrointestinal tract, including neoplasms of true smooth muscle and neural origin, proliferating fibrous lesions, metastatic neoplasms, and primary sarcomas of vascular and adipose origin. Immunohistochemical studies that include CD117 have become invaluable in the classification of mesenchymal lesions arising in the gastrointestinal tract. Treatment of gastrointestinal stromal tumors has historically been involved surgery, but the use of the chemotherapeutic agent imatinib mesylate for advanced disease has made accurate classification even more important. The molecular features have not only allowed us to understand the pathogenesis of these tumors but also have proven to be associated with response to kinase inhibitors.

Polypoid PEComa in the rectum of a 15-year-old girl: case report and review of PEComa in the gastrointestinal tract

PEComa of the gastrointestinal tract, composed of perivascular epithelioid cells with myomelanocytic differentiation, is rare with previous literature limited to 16 case reports. There is a marked female preponderance and approximately one-third of the cases occur in the pediatric age group. We report PEComa with lymph node involvement occurring in the rectum of a 15-year-old girl, treated by surgical resection and adjuvant chemotherapy. The patient is well at 9 months follow-up with neither radiologic nor endoscopic evidence of recurrence. We review the differential diagnosis of intestinal PEComa, which includes malignant melanoma, epithelioid gastrointestinal stromal tumors, clear cell sarcoma of soft parts, alveolar soft part sarcoma, leiomyosarcoma with HMB45 expression, and paraganglioma. Immunohistochemistry can rule out many of these morphologically similar tumors but differentiation from clear cell sarcoma may require reverse transcription-polymerase chain reaction. We discuss the determination of pathologic features indicative of malignancy in PEComa, which is complicated in the gastrointestinal tract due to the small number of cases, variability of pathologic features reported, and inconsistent reporting of outcome. All 4 tumors reporting early recurrence or progression were greater than 5 cm in size and had areas of coagulative tumor necrosis. In addition, high nuclear grade and lymphovascular invasion were seen in 2 of these 4 cases. We propose that a minimum dataset for gastrointestinal PEComa should include these features along with mitotic count, infiltrative border, and tumor stage analogous to that used in colorectal carcinoma.

Role of imatinib in the management of early, operable, and advanced GI stromal tumors (GISTs)

Gastrointestinal stromal tumors (GISTs), the most common sarcoma of the GI tract, have unique kinase mutations that serve as targets for medical therapy. This article reviews the data supporting the use of the tyrosine kinase inhibitor (TKI) imatinib in GIST patients, and how this treatment should be combined with surgical resection (when possible) to optimize patient outcomes. Although surgical resection remains the mainstay of treatment for these tumors, patients with resected GISTs have high relapse rates that can be reduced by 1 year of adjuvant imatinib. Data also support the use of imatinib for patients with recurrent or unresectable GIST. In these patients the drug should be continued until progression, intolerance, or the patients are rendered resectable. Patients with advanced GIST who are successfully resected after imatinib treatment should be placed back on imatinib postoperatively. Patients who develop generalized progression (progression at 2 or more sites) on imatinib should move to other treatments, such as newer TKIs or other targeted approaches currently under study. Genotyping of the tumor should be considered in all pediatric GISTs and high risk adult GISTs, especially if there is progression on imatinib. Quality of life and the cost/benefit of new therapies are important issues for further study in patients with GIST.

Imatinib in the treatment of solid tumours

The extraordinary success of imatinib in gastrointestinal stromal tumors (GIST) represents a model for molecularly targeted therapy for other solid tumors. Research is currently going to identify the molecular basis of mechanisms of action and drug resistance. In this article, we review recent advances in the clinical management of patients with GISTs treated with imatinib, but also of patients with dermatofibrosarcoma protuberans, chordoma, aggressive fibromatosis, and some other common solid tumors treated with this drug. We reviewed the knowledge of the molecular mechanisms that are basic to imatinib effects in these tumors.

Duodenal epithelioid gastrointestinal stromal tumor with prominent granular cell features

Gastrointestinal stromal tumors are a group of mesenchymal tumors arising from the wall of the gastrointestinal tract that are characterized by activating mutations in KIT or PDGFRA. Their proper recognition is important clinically because of their potential responsiveness to targeted therapies. We report a case of duodenal gastrointestinal stromal tumor with a highly unusual epithelioid morphology that had an appearance reminiscent of a steroid producing neoplasm, such as an adrenal cortical neoplasm or, alternatively, a renal cell carcinoma variant. The recognition of the current tumor as a duodenal gastrointestinal stromal tumor was prompted by its apparent location in the duodenal wall. Ancillary immunohistochemical and molecular sequence analyses were necessary to confirm the diagnosis as a gastrointestinal stromal tumor. The current case illustrates the importance of considering gastrointestinal stromal tumor in the differential diagnosis of any epithelioid tumors in the gastrointestinal tract or the abdominal-pelvic cavity.

Consensus approaches to best practice management of gastrointestinal stromal tumors

Gastrointestinal stromal tumors are rare mesenchymal tumors of the gastrointestinal tract. Progress in diagnosis has led to increased recognition of this disease, and the availability of effective, molecularly targeted therapy has revolutionised its management. Treatment of metastatic gastrointestinal stromal tumors with imatinib has led to unprecedented improvements in progression free and overall survival and there are ongoing investigations into the optimal pre‐operative and adjuvant use of imatinib. Second‐line sunitinib is now available for patients who develop resistance to imatinib, and third‐ and fourth‐line therapies are being investigated in clinical trials. In this ever‐changing environment, evidence from controlled clinical trials and the authors' experience were used to comprehensively outline current best practice management of patients with gastrointestinal stromal tumors.

Management of gastrointestinal stromal tumors

A gastrointestinal stromal tumor (GIST) is a rare mesenchymal malignancy of the gastrointestinal (GI) tract. Malignant GISTs were first defined as a separate entity from a collection of nonepithelial malignancies of the GI tract in the 1980s and 1990s based on pathologic and clinical behavior. The discovery of activating KIT mutations as a near-uniform occurrence in these tumors greatly influenced the classification [1] and revolutionized therapeutic management of these tumors. To meet the next challenges, newer tyrosine kinase inhibitors and targeted agents are being developed with the goal of providing improved response rates or alternative therapies for patients progressing on established agents. In this article, the authors describe the management of GISTs, concentrating on surgical management and targeted therapies.