Gastrointestinal stromal tumors: differential diagnosis

Case report: a rare clinical presentation of a difficult diagnosis of dedifferentiated liposarcoma showing leiomyosarcoma phenotype in the ileocecal region

Dedifferentiated liposarcoma is a malignant lipomatous tumor that rarely occurs in the gastrointestinal tract, including the ileocecal region. In this case, computed tomography and magnetic resonance imaging showed no fatty mass located in the mesenteric or submucosal lesion, and positron emission tomography-computed tomography showed a high maximum standardized uptake value, collectively indicating the gastrointestinal stroma tumor and lymphoma. The pathological findings resemble leiomyosarcoma; the immunohistochemistry findings including mouse double minute 2 homolog and cyclin D-dependent kinase-4 and amplification of mouse double minute 2 homolog in fluorescence in situ hybridization just favored the diagnosis of dedifferentiated liposarcoma with leiomyosarcoma phenotype and not leiomyosarcoma. Recently, a new inhibitor for mouse double minute 2 homolog and cyclin D-dependent kinase-4 has been developed, and clinical trials for dedifferentiated liposarcoma are currently ongoing. This could change the treatment strategy drastically compared with other soft tissue sarcomas. Hence, a correct diagnosis of dedifferentiated liposarcoma is required.

Mesocolic schwannoma mimicking gastrointestinal stromal tumor: A case report and review of literature

RATIONALE

Schwannomas are common peripheral nerve tumors originating from Schwann cells, primarily occurring in the head and neck, limbs, and trunk. Schwannomas occurring in the mesocolon are rare and often have no specific manifestations. Abdominal schwannomas need to be differentiated from common abdominal tumors such as gastrointestinal stromal tumors.

PATIENT CONCERNS

We report a case of a mesocolic schwannoma in a 59-year-old female presenting with gastrointestinal symptoms of acid reflux. At an outside hospital, gastroscopy, colonoscopy, and abdominal computed tomography scans revealed a soft tissue mass adjacent to the greater curvature of the stomach, leading to a suspicion of a gastric mesenchymal tumor.

DIAGNOSES

Mesocolic schwannoma.

INTERVENTIONS

Laparoscopy was performed at our hospital. Intraoperatively, the tumor was found to be closely related to the transverse colon and was initially diagnosed as a mass originating from the transverse colon. Consequently, a resection of the mass along with the adherent portion of the transverse colon was performed. Postoperative pathology and immunohistochemistry confirmed that the tumor was a schwannoma of the mesentery and did not originate from the transverse colon.

OUTCOMES AND LESSONS

Schwannomas can be distinguished from gastrointestinal stromal tumors by immunohistochemical staining, and surgical treatment is effective for benign schwannomas.

Different Shades of Desmoid-Type Fibromatosis (DTF): Detection of Noval Mutations in the Clinicopathologic Analysis of 32 Cases

BACKGROUND

Desmoid-type fibromatosis (DTF) is a locally aggressive myofibroblastic/fibroblastic neoplasm with a high risk of local recurrence. It has a variety of histologic features that might confuse diagnosis, especially when detected during core needle biopsy. The Wnt/β-catenin pathway is strongly linked to the pathogenesis of DT fibromatosis.

METHOD

This study examined 33 desmoid-type fibromatoses (DTFs) from 32 patients, analyzing its clinical characteristics, histologic patterns, occurrence rates, relationship with clinical outcomes, immunohistochemical and molecular findings.

RESULTS

The DTFs exhibit a range of 1 to 7 histologic patterns per tumor, including conventional, hypercellular, myxoid, hyalinized/hypocellular, staghorn/hemangiopericytomatous blood vessels pattern, nodular fasciitis-like, and keloid-like morphology. No substantial association was found between the existence of different histologic patterns and the clinical outcome. All thirty-three (100%) samples of DTF had a variable percentage of cells that were nuclear positive for β-catenin. An NGS analysis detected novel non-CTNNB1 mutations in two DTFs, including BCL10, MPL, and RBM10 gene mutations.

CONCLUSIONS

This study reveals a diverse morphology of DTFs that could result in misdiagnosis. Therefore, surgical pathologists must comprehend this thoroughly. Also, the importance of the newly identified non-CTNNB1 gene mutations is still unclear. More research and analyses are needed to completely grasp the clinical implications of these mutations.

Primary leiomyosarcoma of the colon: a report of two cases and review of literature

Introduction

Primary leiomyosarcoma (LMS) of the colon is a rare neoplasm and constitutes less than 0.1% of all colon malignancies. These tumors are more aggressive and have poorer prognoses than other gastrointestinal tumors, including gastrointestinal stromal tumors (GIST) or adenocarcinomas. The authors herein report two cases and review the literature to highlight the epidemiology, diagnosis, treatment and prognosis of this uncommon malignancy.

Case report

The authors reported two very rare cases of LMS of left colon, which referred to our institution with symptoms of abdominal pain. After the initial investigations, patients were diagnosed with primary colonic leiomyosarcoma that underwent laparotomy. In both cases pathological examination revealed a spindle cell tumor growing circumferentially and transmurally in the colon. Final immunohistochemistry were positive with SMA, CK and desmin without the expression of GIST markers (CD117, CD34 and DOG1) that confirmed leiomyosarcoma. One patient was diagnosed with diffused peritoneal metastasis at 6 months postoperatively and he died after 2 months of paliative care, another one is still on active surveillance.

Discussion

LMS of the colon is a really rare entity and is only presented in clinical case reports. LMS has non-specific symptoms and is commonly diagnosed when it reaches a large size. Surgery is a mainstay treatment option. Nowadays, there is no clear evidence for the effectiveness of chemotherapy and radiation therapy.

Conclusion

LMS is a rare neoplasm of colon. For the time being, there is no guidelines for treatment, but surgery still plays a fundamental role.

Importance of immunohistochemistry in the differential diagnosis of gastric mesenchymal tumors

Although morphology is the key to histological diagnosis, gastric mesenchymal tumors can share very similar growth and cellularity patterns, sometimes being indistinguishable. Therefore, immunohistochemical techniques are going to be crucial in the definitive diagnosis. The objective of this work is to perform an immunohistochemical differential diagnosis of gastric mesenchymal tumors.

Case report: Desmoid fibromatosis diagnosed in a 27-year-old male after being mistaken for a gastrointestinal stromal tumour

Despite being distinct lesions, gastrointestinal stromal tumours (GISTs) and desmoid fibromatosis may appear similar on imaging when they involve the stomach wall or bowel. As a result, they may be confused with one another when initially diagnosed. This report aims to present a case where a desmoid tumour was mistaken for a gastric GIST in a 27-year-old gentleman despite extensive investigation prior to exploratory laparotomy, and why differentiation through pathology, with a focus on the immunohistochemistry profile, is key for proper prognostication and appropriate management, including timely investigation for associated diseases such as Familial Adenomatous Polyposis in patients with desmoid tumours.

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.

Gastric carcinoma with a gastrointestinal stromal tumor - A case report and literature review

Gastric carcinoma (GC) with gastrointestinal stromal tumor (GIST) is encountered very rarely in the clinic, and few cases have been reported in the literature. Here, we present a case involving a 72-year-old man who was diagnosed with gastric antrum adenocarcinoma accompanied by neuroendocrine differentiation and a GIST in the fundus, according to a preoperative examination and postoperative pathology. The patient then underwent a distal radical gastrectomy and GIST resection. After the operation, the patient was administered combined chemo-radiotherapy and subsequently underwent a 9-month follow-up examination. The gene mutations involved in this case were explored via high-throughput sequencing. The high-throughput gene mutation analysis indicated an exon5 mutation in the TP53 gene and copy number amplification of FGF19, CCND1, and FGFR2 in the gastric antrum adenocarcinoma. A gene sequencing analysis of the gastric fundus stromal tumor demonstrated an exon11 non-frame shift deletion mutation in the KIT gene. These findings suggested that this patient's cancer might be sensitive to AZD1775 (a TP53-targeted drug) or targeted drugs such as FGF19, CCND1 and FGFR2, and should be sensitive to imatinib.

Pediatric soft tissue tumor pathology: A happy morpho-molecular union

Since its foundation by remarkably talented and insightful individuals, prominently including Pepper Dehner, pediatric soft tissue tumor pathology has developed at an immense rate. The morphologic classification of tumoral entities has extensively been corroborated, but has also evolved with refinement or realignment of these classifications, through accruing molecular data, with many derivative ancillary diagnostic assays now already well-established. Tumors of unclear histogenesis, classically morphologically undifferentiated, are prominent amongst pediatric sarcomas, however, the classes of undifferentiated round- or spindle-cell-tumors-not-otherwise-specified are being dismantled gradually with the identification of their molecular underpinnings. Within recent years, for example, numerous subcategories of 'Ewing-like' round cell sarcoma have emerged. Such advances have provided the basis for novel diagnostic and prognostic sub-classifications. Efforts at defining cell- or lineage-of-origin for several tumor types have produced interesting insights especially for rhabdomyosarcoma. The remarkably early onset of pediatric sarcomas defies the theory necessitating stochastic accumulation of several somatic mutations for cancer development and indeed, these tumors may be remarkably genomically stable, often belying their aggressive nature. Much is coming to light recently regarding the role of epigenetic modifications in the evolution of these sarcomas. Indeed the morphologic features of embryonal tumors generally (not just sarcomas) may be highly reminiscent of arrested differentiation, and given the tight epigenetic regulation of cell fate determination and cell identity maintenance, a theory of epigenetically-driven oncogenesis sits easily with these tumors. The age-delimited distinct biologies of 'pediatric' and adult GIST are intriguing, particularly, the SDH-deficient 'pediatric' form, driven by a metabolic defect, but resulting in epigenetic dysregulation with genome-wide DNA methylation changes. There is little doubt that many of the gaps in our understanding of pediatric sarcoma biology will be filled by a deeper appreciation of the role of dysregulated epigenetics including chromatin biology, perhaps best exemplified in malignant rhabdoid tumor. The field of pediatric soft tissue tumor pathology grows ever more interesting. Importantly though, it must be emphasized, that none of this progress could have occurred, or indeed continue, without the initial step of accurate diagnosis, founded solidly on morphology - thank you Pepper for your unparalleled contributions to this field! The opportunity to be your apprentice for five years has been a bigger and more positive influence than words can express.

Primary gastrointestinal stromal tumour of the ileum pre-operatively diagnosed as an abdominal abscess

The present case report described the acute presentation, diagnosis and management of a primary gastrointestinal stromal tumour (GIST) of the ileum. A male patient (age, 51 years) was admitted to Maggiore Hospital (Parma, Italy) due to presenting with fever, dysuria and lower abdominal pain. Ultrasonography and computed tomography showed a 7,5×5,5-cm pelvic mass containing air and purulent fluid indicative of an intraperitoneal abscess. The patient was subjected to diagnostic laparoscopy, which revealed a huge, soft cystic mass arising from the small bowel. The procedure was then converted to an open exploration through a midline incision. Ileal resection including a Meckel's diverticulum was performed. Macroscopic examination revealed that the cystic mass was filled with a large amount of pus, probably due to communication between the tumour mass and the small bowel lumen. In fact, the surgical specimen showed enteric leakage from the ileal mucosal ulcer into the tumour mass. Histopathology and immunohistochemistry of the abscess wall identified a spindle-cell mesenchymal-type, c-KIT-positive neoplasm. The post-operative course was uneventful and adjuvant imatinib mesylate was administered for 1 year. Follow-up by computed tomography demonstrated no tumour recurrence at 72 months after surgery.

"Wild type" GIST: Clinicopathological features and clinical practice

Gastrointestinal stromal tumor (GIST) is a mesenchymal tumor of the gastrointestinal tract. Mutation of KIT and PDGFRA genes is implicated in the tumorigenesis. Approximately 10% of GISTs do not harbor mutation of these genes, and they are designated as "wild type" GIST. They are classified into succinate dehydrogenase (SDH)-deficient and non-SDH-deficient groups. SDH-deficient group includes Carney triad and Carney Stratakis syndrome. The patients are young women. Tumors occur in the antrum of the stomach, and tumor cells are epithelioid. Lymph node metastasis is frequent. The non-SDH-deficient group includes neurofibromatosis (NF) type 1 and GISTs with mutations of BRAF, KRAS, and PIK3CA and with the ETV6-NTRK3 fusion gene. GIST in NF occurs in the small intestine, and tumor cells are spindle shaped. GIST with BRAF mutation arises in the small intestine. Attention to the age, gender, family history and other neoplasms may raise the prediction of syndromic disease. Location of the tumor, morphology, and pleomorphism of the tumor cells are further informative. Lymphovascular invasion should be carefully evaluated. The determination of KIT expression is essential for the diagnosis. When wild type GIST is suspected, intensive genetic analysis is required. Further, a careful and long-time observation is recommended.

Fever,Weight Loss and Early Satiety due to Gastric Inflammatory Myofibroblastic Tumor; Case Report and Literature Review

Gastric inflammatory myofibroblastic tumor (IMT) is a rare tumor with and unpredictable prognosis usually find in young adults. We present an 18-yearold man with gastric IMT. He complained of epigastric pain, intermittent fever and night sweating associated with weight loss since two years ago. Physical examination showed anemic and cachestic features with mild abdominal tenderness in palpitation as well as an abdominal mass in epigastrium. Abdominal CT scan revealed a huge mass that was arising from the stomach. Upper endoscopy revealed a submucosal lesion in fundus of stomach of approximately 8cm. Endoscopic ultrasound showed a large sub-mucosal non homogenous fundal mass with areas of calcification. The patient underwent laparoscopic partial gastrectomy. Histopathologyand immunohistochemistryevaluation revealed an IMT.

Primary gastric inflammatory myofibroblastic tumor in an adult-case report with brief review

The term inflammatory myofibroblastic tumor more commonly referred to as "pseudostumor ", denotes a pseudosarcomatous inflammatory lesion that contains spindle cells, myofibroblasts, plasma cells, lymphocytes and histiocytes. It exhibits a variable biological behavior that ranges from frequently benign lesions to more aggressive variants. Inflammatory myofibroblastic tumor (IMT) of the stomach is extremely rare and its prognosis is unpredictable. We present a 45-year-old diabetic man with a gastric Inflammatory myofibroblastic tumor. The histopathological and immunohistochemical analysis was the key to reach diagnosis.

Gastrointestinal stromal tumors: diagnosis, therapy and follow-up care in Austria

Optimal treatment for patients suffering from gastrointestinal stromal tumors (GIST) is based on an interdisciplinary treatment approach. Austrian representatives of Medical and Surgical Oncology, Pathology, Radiology, Nuclear Medicine, Gastroenterology, and Laboratory Medicine issued this manuscript on a consensual base within the context of currently available and published literature. This paper contains guidelines and recommendations for diagnosis, therapy, and follow-up of GIST patients in Austria.

Expression of DOG1, CD117 and PDGFRA in gastrointestinal stromal tumors and correlations with clinicopathology

OBJECTIVE

To discuss the significance of DOG1, CD117 and PDGFRA in the diagnosis of gastrointestinal stromal tumors (GISTs), and analyze their correlations with clinicopathological features and risk ranking.

METHOD

DOG1, CD117 and PDGFRA were detected with IHC Envision ldpe-g-nvp in 63 GISTs and 43 cases of non-GISTs, and analyzed for relations with clinicopathological factors (gender, age, location, tumor size, mitotic phase, histology) and risk degree.

RESULTS

The positive expression rate of DOG1, CD117 and PDGFRA in GISTs was 84.1% (53/63), 90.5% (57/63), 53.2% (33/63), respectively. Among the 6 CD117 negative cases, all were DOG1 positive and 5 were PDGFRA positive. Rates in patients with non-GISTs was 11.6%, 16.3%, 6.98%, respectively. Expression of DOG1 and PDGFRA demonstrated no significant variation with gender, age, position, tumor size, mitotic phase, histology, and risk rank. However, CD117 was related with position and histology (P=0.008 and P=0.045), those in the mesentery having a higher positive rate than those derived from stomach, small intestine, colon and rectum (50.0% vs 94.7%, P=0.008). Furthermore CD117 was also highly expressed in spindle and epithele types.

CONCLUSIONS

DOG1 had a good sensitivity and specificity as a kind of newly discovered marker, especially for KIT negative GISTs. However, DOG1, CD117 and PDGFRA cannot be used for assessing the rish of patients.

Soft tissue tumors of uncertain origin

Many soft tissue tumors of childhood lack obvious differentiation toward a defined mesenchymal tissue type or have a phenotype that does not correspond to any defined normal tissue. These challenging tumors are currently regarded as neoplasms of uncertain differentiation. Nonetheless, there have been great strides in the understanding of their pathologic and genetic features and biologic underpinnings. The application of new genetic information to the pathologic diagnosis among this group of tumors is an emerging area in diagnostic pediatric pathology. This article reviews the clinicopathologic features of tumors of uncertain and/or miscellaneous origin, with an emphasis on the unique aspects of these neoplasms in children and adolescents, use of diagnostic adjuncts, and differential diagnosis.

Rare gastric inflammatory myofibroblastic tumor in an adult woman: a case report with review of the literature

Inflammatory myofibroblastic tumor (IMT) of the stomach is extremely rare and its prognosis is unpredictable. We present a 37-year-old woman with a gastric IMT. She presented epigastric pain since 2 months, anemia and weight loss associated. Physical examination showed cutaneous pallor and mild abdominal tenderness in the epigastrium. Abdominal ultrasonography showed a tumor near the pancreas and the CT scan revealed that the lesion was arising from the stomach. Upper endoscopy showed a submucosal lesion of approximately 7.5 cm located in the posterior wall of the gastric body such as a gastrointestinal stromal tumor (GIST). The patient underwent a subtotal gastrectomy and Billroth I reconstruction. The histopathological and immunohistochemical analysis revealed an IMT that originated from the gastric wall.

Exon 11 mutations, Ki67, and p16(INK4A) as predictors of prognosis in patients with GIST

Prognostic biomarkers for GIST are under investigation. The aim of this study was to assess whether exon 11 mutations, Ki67, and p16(INK4A) are predictors of prognosis in GIST. Consecutive GIST cases (n=84) had their specimens evaluated for exon 11 mutations and expression of Ki67 and p16(INK4A). Surgical cases were categorized according to NIH and Miettinen's classification, and survival was analyzed from hospital database. GISTs were predominately gastric (45%) and with spindle cell morphology (74%). The risk category was very low or low in 28%, intermediate in 23%, and high in 49%. Exon 11 mutation was identified in 29 (48%) out of 60 cases studied. There were 12 point mutations, 10 deletions, 4 duplications, and 3 double mutations. A third of GISTs had either high Ki67 index (>3%) or negativity for p16(INK4A). In multivariate analysis, independent predictors of mortality were Ki67>3% (HR=7.3; P=0.036) and high mitotic index (HR=10.4; P=0.043). There was no association between exon 11 mutations and survival. This study suggests that Ki67>3% is an independent predictor of poor prognosis in patients with GIST. Exon 11 mutations and negativity for p16(INK4A) need further studies to address the prognostic value.

Expression of DOG1, CD117 and PDGFRA in gastrointestinal stromal tumors

AIM: To investigate the significance of expression of discovered on GIST-1 (DOG1), CD117 and platelet-derived growth factor receptor alpha (PDGFRA) in gastrointestinal stromal tumors (GISTs) by analyzing their correlation with clinicopathologic features and risk degree of GISTs.

METHODS: The expression of DOG1, CD117 and PDGFRA was detected by immunohistochemistry in 63 cases of GISTs and 43 cases of non-GISTs. The correlation of expression of DOG1, CD117 and PDGFRA with clinicopathologic factors and risk degree of GISTs was then analyzed.

RESULTS: The positive expression rates of DOG1, CD117 and PDGFRA in GISTs were 84.13% (53/63), 90.48% (57/63) and 3.17% (33/63), respectively. The positive expression rates of DOG1 and CD117 in GISTs were significantly higher than that of PDGFRA (both P < 0.01). Of six CD117-negative cases, all were positive for DOG1 and five positive for PDGFRA. The positive expression rates of DOG1, CD117 and PDGFRA in patients with non-GISTs were 11.63%, 16.28% and 6.98%, respectively. The expression of DOG1 and PDGFRA had no significant association with gender, age, tumor location, tumor size, mitotic phase, histotype, or risk degree, while the expression of CD117 was related with tumor location and histotyoe (P = 0.008, 0.045). Tumors derived from the mesentery, abdominal cavity and epiploon had higher positive rates of CD117 than those derived from the stomach, small intestine, colon and rectum (50.00% vs 94.74%, P = 0.008). CD117 was highly expressed in spindle-cell and epithelial-cell types.

CONCLUSION: Both DOG1 and CD117 are highly expressed in GISTs and can serve as specific diagnostic markers for GISTs. DOG1 has a good sensitivity and specificity in the diagnosis of GISTs, especially KIT-negative GISTs. Detection of DOG1, CD117 and PDGFRA expression can not be used for assessing the risk degree of GISTs.

Protein expression of cancer testis antigens predicts tumor recurrence and treatment response to imatinib in gastrointestinal stromal tumors

Cancer testis antigens (CTAs) have been identified in various tumors as immunological tumor targets. In gastrointestinal stromal tumor (GIST), the prediction of malignant potential remains difficult but is crucial in the era of adjuvant imatinib treatment. Here, we analyzed the impact of CTAs on tumor recurrence and its role on the treatment response to imatinib. The expression of the most frequent CTAs MAGE-A1, MAGE-A3, MAGE-A4, MAGE-C1 and NY-ESO-1 was analyzed by immunohistochemistry. The duration between the initial operation and the tumor relapse was defined as recurrence free survival (RFS). All recurrent cases were treated with imatinib. The tumor response to imatinib was graded according to the modified CT response evaluation criteria. Patients with a CTA positive GIST (n = 23, 27%) had a significantly shorter RFS (p = 0.001) compared to negative cases (n = 63, 73%). The median RFS was 25 months in CTA positive patients and was not reached during the study period in CTA negative patients. According to the established staging criteria CTA positive tumors were predominantly high-risk tumors (p = 0.001). The expression of MAGE-A3 (p = 0.018) and NY-ESO-1 (p = 0.001) were associated with tumor progression under imatinib treatment. A tendency for worse tumor response to imatinib was observed in CTA positive tumors (p = 0.056). Our study confirms the expression of CTAs in GIST and their role as prognostic markers. It also draws attention to the potential impact of CTAs on the tumor response to imatinib.

Diagnosis and treatment of intestinal stromal tumors initially manifesting as gastrointestinal hemorrhage: an analysis of 17 cases

AIM: To improve the understanding, early diagnosis and treatment of intestinal stromal tumors initially manifesting as gastrointestinal bleeding.

METHODS: The clinical data for 17 patients with intestinal stromal tumors initially manifesting as gastrointestinal hemorrhage were analyzed retrospectively, including clinical manifestations, hemoglobin concentration, intestinal computed tomography (CT) imaging data, pathological data, immunohistochemistry data, and follow-up data.

RESULTS: Intestinal stromal tumors initially manifesting as gastrointestinal bleeding occurred more frequently in elderly patients whose average age was 58 years. Males were slightly more likely to suffer from the disease than females. Hematochezia and varying degrees of anemia were the major clinical manifestations. CT scan of the intestine was helpful for finding the tumors showing exophytic growth without lymphatic metastasis. Intestinal tumors, which presented as low-density, sharply marginated, lobulated or unlobulated soft masses, were found in 16 patients on CT scan. These tumors had an average computed tomographic value of 32 Hounsfield units. Enhanced CT scan showed that the majority of tumors exhibited inhomogeneous enhancement. All patients were positive for CD117. Histopathology and immunohistochemistry can help establish a confirmative diagnosis and conduct risk classification. Surgery was the first choice of treatment for the disease.

CONCLUSION: CT scan is helpful in finding intestinal stromal tumors initially manifesting as gastrointestinal bleeding. The prognosis of intestinal stromal tumors could be improved by surgery and biological targeted therapy.

Diagnostic criteria, specific mutations, and genetic predisposition in gastrointestinal stromal tumors

In 1998, gastrointestinal stromal tumor (GIST) emerged as a distinct oncogenetic entity and subsequently became a paradigm of targeted therapies in solid tumors. Diagnosis of GIST relies on both histology and immunohistochemistry. Ninety-five percent of GISTs express either KIT or DOG-1. Approximately 80%-90% of GISTs harbor gain-of-function mutations of either KIT or platelet-derived growth factor receptor alpha polypeptide (PDGFRA) receptor tyrosine kinase (RTK). More than 100 different mutations have been described, some of which are associated with specific clinical and/or histological characteristics. Detection of KIT or PDGFRA mutations is recommended in advanced GISTs because they are highly predictive of tumor response to RTK inhibitors, as well as in KIT-negative cases to confirm diagnosis. In most cases, GISTs are sporadic, but in rare cases, they are related with genetic predisposition, such as neurofibromatosis type 1, Carney triad, Carney-Stratakis syndrome, and inherited KIT or PDGFRA germline mutations.

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.

Primary gastric inflammatory myofibroblastic tumor: a clinicopathologic and immunohistochemical study of 5 cases

Primary gastric inflammatory myofibroblastic tumors are rare. Here we report on 5 such cases (4 males and 1 female, age range 36-45 years). Their presenting symptoms included abdominal mass (5 patients), abdominal pain (4 patients), and upper gastrointestinal hemorrhage (1 patient). Tumor size ranged from 4.5 to 8 cm in the greatest dimension. Histologically, these tumors showed three patterns: myxoid hypocellular, fascicular, and hyalinized. A lymphoplasmacytic infiltrate was present in all 5 tumors. One to two mitotic figures were recognized in 10 high power fields (HPFs) in 4 patients and focally up to 5 in 10HPFs in 1 patient. No prominent nuclear atypia or necrosis was observed. ALK, smooth muscle actin, and vimentin staining were observed in all tumors. One tumor focally expressed desmin. S-100, CD21, CD34, CD35, CD68, and CD117 were negative in all IMTs. The patients were followed up for 2-5 years (mean 3.4 years), and none of them had tumor metastasis or died. Only one patient developed local recurrence and is now alive with no evidence of disease after the second surgery (11 months after the second surgery). Our results indicate that primary gastric IMTs have an intermediate behavior as seen at other sites.

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.

Advances in imaging diagnosis of gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GIST) are the most common non-epithelial tumors. In recent years, the development of imaging technology has resulted in an increase in diagnostic yield of GIST. In this article, we will review the recent advances in imaging diagnosis of GIST.

Gastrointestinal stromal tumors: Recommendations on diagnosis, therapy and follow-up care in Austria

Adequate treatment of gastrointestinal stromal tumors (GISTs) is linked to an interdisciplinary treatment approach. Austrian representatives of medical oncology, surgery, pathology, radiology and gastroenterology have issued this consensus manuscript within the context of currently available and published literature. The paper contains guidelines and recommendations for diagnosis, therapy and follow-up of GIST patients in Austria.

A distinctive novel epitheliomesenchymal biphasic tumor of the stomach in young adults ("gastroblastoma"): a series of 3 cases

This report describes 3 cases of a distinctive, hitherto unreported gastric epitheliomesenchymal biphasic tumor that differs from other biphasic tumors of the stomach and elsewhere: carcinosarcoma, biphasic synovial sarcoma, teratoma, and mixed tumor. The tumors occurred in young adults, 2 males and 1 female, of ages 19, 27, and 30 years. Two tumors were located in the greater curvature in the gastric body and one in the antrum. The tumors measured 5, 6, and 15 cm in maximum diameter, and their mitotic rates were 0, 4, and 30 mitoses per 50HPF. There were 2 components: uniform oval or spindled cells in diffuse sheets, and clusters or cords of epithelial cells occasionally forming glandular structures with small lumens. The epithelial elements were positive for keratin cocktail AE1/AE3, keratin 18, and partly for keratin 7, but were negative for keratins 5/6, 20 and epithelial membrane antigen. The spindle cells were positive for vimentin and CD10. All components were negative for CD34, CD99, estrogen receptor, KIT, smooth muscle actin, desmin S100 protein, p63, calretinin, chromogranin, synaptophysin, CDX2, and thyroid transcription factor 1. In situ hybridization for SS18 rearrangement was negative in all cases separating this tumor from synovial sarcoma. All 3 patients were alive after follow-up of 3.5, 5, and 14 years. Because these tumors have some resemblance to blastomas of other organs, we propose the term "gastroblastoma" for this distinctive, at least low-grade malignant epitheliomesenchymal tumor of the stomach.

[Gastrointestinal stromal tumors: recommendations for diagnosis, treatment and aftercare in Austria]

Diagnosis and treatment of gastrointestinal stromal tumors (GIST) requires an interdisciplinary treatment approach. This strategy should be reflected by the content of this article. Austrian representatives of 'GIST relevant' specialties authored this publication on a consensual base. This manuscript should be regarded as a guideline for 'GIST involved' colleagues in Austria.

Clear-cell sarcoma of the small intestine detected by FDG-PET/CT during comprehensive examination of an inflammatory reaction

Clear-cell sarcoma (CCS) is a rare, malignant, soft-tissue tumor, which involves the extremities, particularly the foot and foot joint tendons and aponeuroses. It is morphologically similar to but histochemically distinct from malignant melanoma. CCS arising in the gastrointestinal tract has rarely been reported. The prognosis of CCS is reportedly poor because of the high incidence of metastases at the time of initial diagnosis and the high frequency of recurrence. We report a case of early-stage CCS of the small intestine detected by (18)F-fluoro-2-deoxy D-glucose Positron Emission Tomography/Computed Tomography (FDG-PET/CT) during the comprehensive examination of an inflammatory reaction. In this case, FDG-PET/CT clearly visualized the lesion, which was difficult to detect by contrast CT.

Gastrointestinal stromal tumor of the uterus: a case report with genetic analyses of c-kit and PDGFRA genes

The author reports a very rare case of a gastrointestinal stromal tumor in the uterus. A 74-year-old woman was admitted to our hospital because of pelvic pain. Imaging modalities showed a large tumor of the posterior aspect of the uterus, and enucleation was performed. The tumor was attached to the posterior uterus, similar to subserosal leiomyoma. No attachment to the gastrointestinal organs was recognized. The tumor was soft, tan, and measured 13 x 15 x 12 cm. The tumor consisted of cellular spindle cells with focal necrotic areas. Mitotic figures were noted in 3 of 50 high-power fields. The tumor cells were positive for KIT, CD34, platelet-derived growth factor receptor alpha, and vimentin, but negative for alpha-smooth muscle actin, S100 protein, p53 protein, HMB45, and desmin. Ki-67 labeling was 3%. Five normal uteruses used as controls showed KIT-positive Cajal-like mesenchymal cell scattering in the myometrium. Genetic analyses of the c-kit gene (exons 9, 11, 13, and 17) and platelet-derived growth factor receptor alpha gene (exons 12 and 18) revealed a point mutation at codon 559 (GTT-->GAT) of exon 11 of the c-kit gene. Other exons showed no abnormalities. This case shows that gastrointestinal stromal tumor may occur in the uterus.

Diagnostic challenges of motility disorders: optimal detection of CD117+ interstitial cells of Cajal

AIMS

Several gastrointestinal motility diseases are associated with altered numbers of interstitial cells of Cajal (ICC), and testing for alterations in numbers of ICC has been proposed as one way to improve routine diagnosis in motility diseases. However, the protocols currently used to visualize ICC in formalin-fixed paraffin-embedded (FFPE) tissue using antibodies to CD117 have not been optimized for studying motility disorders. The aims of this study were therefore to determine the optimal protocol using FFPE tissue, determine normal values for ICC in non-neoplastic human colon, and compare results with those obtained using immunofluorescence (IF).

METHODS AND RESULTS

Non-neoplastic tissue was collected from patients undergoing resection for colonic cancer and fixed for both light (FFPE) and IF testing. Sections were processed for standard immunohistochemistry using different primary antibodies in conjunction with variations in antigen retrieval [ethylenediamine tetraacetricacid (EDTA), citrate], antibody dilution, blocking and detection (Mach2, Mach3, Envision+). Best results were obtained with EDTA retrieval, the DAKO CD117 antibody and Mach3 detection.

CONCLUSIONS

The optimized protocol presented improved CD117 detection in FFPE tissues and showed good concordance with overall localization of CD117-immunoreactive ICC as detected by IF. As such, this protocol may be more useful than current diagnostic procedures in motility disorders.

Keratin-positive gastrointestinal stromal tumor of the stomach mimicking gastric carcinoma: diagnosis confirmed by c-kit mutation analysis

In routine practice, gastrointestinal stromal tumor (GIST) can usually be identified with relative ease on the basis of a rather simple immunohistochemical panel besides its characteristic morphology. Still, serious differential diagnostic problems may arise because of the heterogeneity of these tumors in both morphologic appearance and clinical behavior. In our case, we present a metastatic, ulcerative, hemorrhagic GIST with epithelioid appearance, which displayed diffuse pan cytokeratin (AE1/AE3) positivity beside CD117 expression. As carcinomas may also be CD117-positive, definitive diagnosis was confirmed by the detection of a hexanucleotide deletion in the exon 11 of c-kit. This case demonstrates that although gastric carcinoma more commonly ulcerates or causes hemorrhage than GIST, keratin-positive GIST should also be considered from a differential diagnostic point of view. In these cases, c-kit mutation analysis may be necessary.

Estrogen and progesterone receptors expression in gastrointestinal stromal tumors and intramural gastrointestinal leiomyomas

Gastrointestinal stromal tumors (GISTs) and leiomyomas of the gastrointestinal tract both may present as intramural smooth muscle cell tumors. Immunohistochemically, these tumors demonstrate different spectrums of protein expression, which helps in differential diagnosis. Leiomyomas of the uterine type are similar by the spectrum of protein expression to gastrointestinal leiomyomas, but they express in addition both estrogen (ER) and progesterone (PR) receptors, which makes hormonal therapy possible for these tumors. In the current study, we investigated expression of ER and PR in GISTs and intramural gastrointestinal leiomyomas. Our data demonstrate that none of the 22 cases of gastrointestinal leiomyomas nor 19 cases of GIST were positive for either ER or PR expression. In contrast, leiomyomas of the uterine type were strongly positive for both ER and PR. Our data demonstrate that GIST and gastrointestinal leiomyomas differ from leiomyomas of the uterine type by the expression of ER and PR. Immunostaining for ER and PR may be a useful tool to distinguish these tumors and more precisely to plan further clinical interventions.