Ki-67 labelling index is related to the risk classification and prognosis of gastrointestinal stromal tumours: a retrospective study.

BACKGROUND AND AIMS: Gastrointestinal stromal tumours (GISTs) are the most common mesenchymal tumours of the digestive tract with malignant potential. The current risk classification standard is unable to accurately evaluate the invasiveness and clinical outcomes of GISTs. Ki-67 labelling index (LI) may be an effective indicator in assessing tumour invasiveness and prognosis, however, its exact value in GISTs is still uncertain. The aims of our study were to evaluate the correlation of the Ki-67 LI and clinicopathological features of GISTs and to assess the potential value of the Ki-67 LI in GISTs classification and prognosis. METHODS: The clinical, pathological and prognostic data were collected and analysed to identify the independent influential factors of GISTs risk stratification and the predictors of GISTs prognosis. RESULTS: The Ki-67 LI was significantly associated with the clinicopathological features of tumour progression (P<0.05). It was an independent influential factor of GISTs risk classification (odds ratio: 1.322; 95% confidence interval: 1.031-1.696) (P=0.028), and the area under the curve (AUC) value of the Ki-67 LI on the discrimination ability of GISTs risk stratification was 0.906 (P<0.001). The optimal cutoff value of the Ki-67 LI was 6% (sensitivity of 87.5% and specificity of 76.2%), and patients with Ki-67 LI≥6% exhibited significantly poorer progression-free survival (PFS) than those with Ki-67 LI<6% (P<0.001). The AUC value of the Ki-67 LI for predicting PFS in postoperative patients was 0.813 (P=0.03). CONCLUSIONS: The Ki-67 LI has appreciated value to predict the risk grade and prognosis of GISTs. Patients with Ki-67 LI≥6% are prone to recurrence and metastasis after operation and may need a close follow-up.

Next-generation sequencing demonstrates the rarity of short kinase variants specific to quadruple wild-type gastrointestinal stromal tumours.

AIM: There is no known specific biomarker or genetic signal for quadruple wild-type (qWT) gastrointestinal stromal tumours (GISTs). By next-generation sequencing (NGS) of different GIST subgroups, this study aimed to characterise such a biomarker especially as a potential therapeutic target. METHODS AND RESULTS: An NGS panel of 672 kinase genes was applied to DNA extracted from 11 wild-type GISTs (including three qWT GISTs) and 5 KIT/PDGFRA mutated GISTs. Short variants which were present in qWT GISTs but no other GIST subgroup were shortlisted. After removing common population variants, in silico-classified deleterious variants were found in CSNK2A1, MERTK, RHEB, ROCK1, PIKFYVE and TRRAP. None of these variants were demonstrated in a separate cohort of four qWT GISTs. CONCLUSIONS: Short kinase variants which are specific to qWT GISTs are rare and are not universally demonstrated by this whole subgroup. It is therefore possible that the current definition of qWT GIST still covers a heterogenous population.

[To improve the understanding of CD117-negative gastrointestinal stromal tumor].

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor of the digestive tract. The diagnosis of GIST relies mainly on clinicopathological features, tumor cell morphology and immunohistochemical marker CD117 (c-Kit). However, some tumors (about 3%-4%) have clinicopathological features of GIST but do not express CD117. To determine whether these lesions are true GIST, it is necessary to raise awareness of CD117-negative GIST. This article discusses the immunohistochemical features, gene mutations, prognosis and efficacy of targeted drugs of CD117-negative GIST. Research results suggest that CD117-negative GIST lacks KIT expression but has typical clinical, histopathological and cytogenetic features. These tumors have KIT and/or PDGFRA mutations, or are wild type. Because most KIT-negative GISTs contain PDGFRA or KIT mutation, pathologists and oncologists should not exclude GIST diagnosis based on negative immunohistochemical staining of KIT. It is known that approximately 30% of PDGFRA mutations may be sensitive to imatinib, and patients with such tumors may benefit from imatinib, so imatinib treatment should not be empirically denied in these patients.

Gastrointestinal stromal tumors (GISTs) with remarkable cystic change: a specific subtype of GISTs with relatively indolent behaviors and favorable prognoses.

PURPOSE: Gastrointestinal stromal tumors (GISTs) are typically solid neoplasms with small cystic change detected occasionally but in rare instances may present predominantly as cystic lesions. The histopathologic features and prognoses of cystic GISTs (cGISTs) are poorly understood. METHODS: We herein reviewed 20 cGISTs resected or consulted in our institution from January 1, 2003 to December 31, 2014. RESULTS: Of the 20 patients included, the mean age was 61 years and the male-to-female ratio was 9:11. The original locations were the stomach (n = 10, 50%), the small intestine (n = 9, 45%) and the omentum (n = 1, 5%). Indistinct diagnosis or misdiagnosis was established in 15 cases based only on preoperative radiology. Grossly, the cystic component made up the bulk of masses and was filled by dark bloody fluid and necrotic debris in 18 cases. Microscopically, cyst wall was composed of neoplastic spindle (n = 14, 70%)/epithelioid cells (n = 6, 30%) and collagenous fiber, with necrotic debris and granulation tissue lining on the inner surface. cGISTs resembled their solid counterparts in terms of morphology and immunohistology but demonstrated fewer malignant parameters. c-kit or PDGFRα mutations were detected in eleven cases with the remaining being wild type for these two mutations. Although classified as intermediate or high (3 and 17, respectively) risk of recurrence according to modified National Institute of Health criterion, most patients with cGISTs experienced long-term recurrence-free survival without adjuvant imatinib. CONCLUSIONS: Cystic GISTs is a relatively indolent subset of GISTs with favorable prognoses and adjuvant imatinib should be a prudent consideration.

Radiomics nomogram for predicting the malignant potential of gastrointestinal stromal tumours preoperatively.

OBJECTIVE: To develop and evaluate a radiomics nomogram for differentiating the malignant risk of gastrointestinal stromal tumours (GISTs). METHODS: A total of 222 patients (primary cohort: n = 130, our centre; external validation cohort: n = 92, two other centres) with pathologically diagnosed GISTs were enrolled. A Relief algorithm was used to select the feature subset with the best distinguishing characteristics and to establish a radiomics model with a support vector machine (SVM) classifier for malignant risk differentiation. Determinant clinical characteristics and subjective CT features were assessed to separately construct a corresponding model. The models showing statistical significance in a multivariable logistic regression analysis were used to develop a nomogram. The diagnostic performance of these models was evaluated using ROC curves. Further calibration of the nomogram was evaluated by calibration curves. RESULTS: The generated radiomics model had an AUC value of 0.867 (95% CI 0.803-0.932) in the primary cohort and 0.847 (95% CI 0.765-0.930) in the external cohort. In the entire cohort, the AUCs for the radiomics model, subjective CT findings model, clinical index model and radiomics nomogram were 0.858 (95% CI 0.807-0.908), 0.774 (95% CI 0.713-0.835), 0.759 (95% CI 0.697-0.821) and 0.867 (95% CI 0.818-0.915), respectively. The nomogram showed good calibration. CONCLUSIONS: This radiomics nomogram predicted the malignant potential of GISTs with excellent accuracy and may be used as an effective tool to guide preoperative clinical decision-making. KEY POINTS: • CT-based radiomics model can differentiate low- and high-malignant-potential GISTs with satisfactory accuracy compared with subjective CT findings and clinical indexes. • Radiomics nomogram integrated with the radiomics signature, subjective CT findings and clinical indexes can achieve individualised risk prediction with improved diagnostic performance. • This study might provide significant and valuable background information for further studies such as response evaluation of neoadjuvant imatinib and recurrence risk prediction.

Tumor del estroma gastrointestinal: presentación de caso / Gastrointestinal stromal tumor: case report

Fundamento: los tumores del estroma gastrointestinal, conocidos en inglés como gastrointestinal stromal tumors, son tumores mesenquimales que aparecen en cualquier sitio del tracto gastrointestinal. Muchos de los cuales suelen ser pediculados y de difícil diagnóstico preoperatorio. Objetivo:exponer un caso de un tumor del estroma gastrointestinal de localización poco frecuente en duodeno, más raro aún su ubicación en yeyuno. Caso clínico: paciente masculino de 77 años de edad que presenta un tumor del estroma gastrointestinal de localización en yeyuno fue atendido en el Hospital Universitario Amalia Simoni, por el servicio de urgencia en el periodo 2016-2017. Conclusiones: los tumores mesenquimales son pocos frecuentes y los del estroma gastrointestinal lo son aún más, donde la localización yeyunal los menos encontrados y en su mayoría el diagnóstico se realiza durante el acto quirúrgico(AU)

Background: the gastrointestinal stromal tumors, are mesenchymal tumors that appear in any place of gastrointestinal tract. Many of them can be pediculate and difficult pre-operatory diagnosis. Objective: to explain a case of gastrointestinal stromal tumor of difficult localization in duodenum but it is even stranger to find it in jejune. Clinical case: a 77-year-old male patient who presents a gastrointestinal stromal tumor located in jejune, he was attended in Amalia Simoni University Hospital, by the emergency services, in the period of 2016-2017. Conclusions:the mesenchymal tumors are not frequent and those of gastrointestinal stroma are even rarer but, being the localization jejunal less found and in its majority the diagnosis is made during the surgical act(AU)

The assessment of different risk classification systems for gastrointestinal stromal tumors (GISTs): the analytic results from the SEER database.

BACKGROUND: Although various risk classification systems for GISTs have been proposed, the optimum one remains uncertain. In the present study, we compared the prognostic stratification of different risk classification systems for GIST patients. METHODS: We reviewed those patients who were pathologically diagnosed with GISTs in the SEER database between 2009 and 2014. All patients were classified into different risk groups according to the NIH criteria, AFIP criteria and AJCC staging system, respectively. The prognostic differences between different risk groups were compared and clinicopathologic features were analyzed. RESULTS: The prognosis of small intestinal GISTs was not significantly different from that of gastric GISTs. For gastric GIST patients, there was no significant prognostic difference between very low risk and low risk group according to the NIH and AFIP criteria. However, the prognostic stratification for two groups could be improved by the AJCC staging system. For small intestinal GIST patients, the prognostic difference between low risk and intermediate risk group was not stratified properly by the NIH and AFIP criteria. However, the prognostic difference between two groups could reach statistical significance according to the AJCC staging system. Unlike gastric GISTs, tumor size was not identified as an independent factor influencing the prognosis of small intestinal GISTs. CONCLUSIONS: The AJCC staging system could provide a better prognostic stratification for GIST patients compared with the NIH and AFIP criteria, regardless of gastric or small intestinal tumor. However, primary tumor location and tumor size may be reconsidered and revised in the risk classification system.

Recurrence-Free Survival After Resection of Gastric Gastrointestinal Stromal Tumors Classified According to a Strict Definition of Tumor Rupture: A Population-Based Study.

BACKGROUND: In gastrointestinal stromal tumors (GISTs), rupture is a high-risk feature and an indication for adjuvant treatment; however, the independent impact of rupture on prognosis is uncertain and the term is inconsistently defined. In the present study, a previously proposed definition of 'tumor rupture' was applied on a population-based cohort of gastric GISTs. METHODS: Patients undergoing surgery for non-metastatic gastric GISTs from 2000 to 2015 were identified in the regional sarcoma database of Oslo University Hospital. Tumor rupture included spillage or fracture, piecemeal resection, incisional biopsy, blood-tinged ascites, gastric perforation, and microscopic adjacent infiltration. Minor defects of tumor integrity were not considered rupture, i.e. core needle biopsy, peritoneal tumor penetration, superficial peritoneal rupture, and R1 resection. Risk was assessed according to the modified National Institutes of Health consensus criteria. RESULTS: Among 242 patients, tumor rupture occurred in 22 patients and minor defects of tumor integrity occurred in 81 patients. Five-year recurrence-free survival (RFS) for patients with tumor rupture, minor defects of tumor integrity, and no defect was 37, 91, and 96%, respectively (p < 0.001). In the high-risk group, 5 year RFS for patients with rupture was 37%, versus 77% without rupture (hazard ratio 3.56, 95% confidence interval 1.57-8.08, p = 0.001). On multivariable analysis, tumor rupture and mitotic index were independently associated with recurrence. Of 13 patients who received adjuvant imatinib after tumor rupture, 11 relapsed. CONCLUSIONS: Tumor rupture according to the present definition was independently associated with recurrence. With tumor rupture, patients relapsed despite adjuvant treatment. Without rupture, prognosis was good, even in the high-risk group.

Recent advances in the diagnosis of soft tissue tumours.

Soft tissue tumours are relatively rare, but are diagnostically challenging as they comprise a large spectrum of diagnostic entities. Substantial advances have been made in recent years in identifying the underlying recurrent chromosomal and genomic alterations in a significant subset of soft tissue tumours, and this continues to enrich our understanding of the biological mechanisms of tumour development and progression. Ongoing validation and integration of these findings into existing pathological-diagnostic algorithms has led to re- or subclassification of diagnostic categories and will continue to shape a more nuanced (and hopefully clinically relevant) tumour classification system in the future. This review provides a selective overview of recent diagnostic or conceptual advances in the categories of peripheral nerve sheath tumours, vascular and adipocytic tumours, round cell and myogenic sarcomas, and gastrointestinal stromal tumours, as well as their underlying molecular mechanisms, some of which have been translated successfully into useful immunohistochemical stains. A thorough and critical validation of newly identified diagnostic markers-acknowledging the fact that some genetic alterations may not necessarily be tumour-specific-and ongoing correlation with clinical and prognostic implications will be necessary in this regard.

Classification of gastrointestinal stromal tumor syndromes.

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract, thought to derive from neoplastic outgrowth of the interstitial cells of Cajal. Building on recent advances in recognition, classification and diagnosis, the past two decades have seen a changing paradigm with molecular diagnostics and targeted therapies. KIT and PDGFRA mutations account for 85-90% of GIST carcinogenesis. However, the remaining 10-15% of GISTs, which until recently were called KIT/PDGFRA wild-type GISTs, have been found to have one of the several mutations, including in the SDHA, B, C, D, BRAF and NF1 genes. Though most of such GISTs are sporadic, a number of families with high incidence rates of GISTs and other associated clinical manifestations have been reported and found to harbor germline mutations in KIT, PDGFRA, SDH subunits and NF1 The goal of this review is to describe the mutations, clinical manifestations and therapeutic implications of syndromic and inherited GISTs in light of recent studies of their clinicopathologic range and pathogenesis.

Image analysis is an excellent tool for quantifying Ki-67 to predict the prognosis of gastrointestinal stromal tumor patients.

We investigated the quantification of Ki-67 staining using digital image analysis (IA) as a complementary prognostic factor to the modified National Institutes of Health (NIH) classification in patients with gastrointestinal stromal tumor (GIST). We examined 92 patients, focusing on the correlation between age, sex, primary tumor site, tumor size, predominant histologic type, mitotic index, modified NIH classification (low/intermediate vs high), Ki-67 quantitation, and recurrence-free survival (RFS). We compared two IA processes for whole slide imaging (WSI) and manually captured image (MCI) methods. A Ki-67 quantitation cutoff was determined by receiver operator characteristics curve analysis. In the survival analysis, the high-risk group of a modified NIH classification, a mitotic count >5 per 20 high-powered fields, and Ki-67 cutoffs of ≥6% and ≥8% obtained by IA of the WSI and MCI methods, respectively, had an adverse impact on RFS. On multivariate analysis, each Ki-67 quantitation method strongly predicted prognosis, more strongly than the modified NIH classification. In addition, Ki-67 quantitation using IA of the MCI method could stratify low or intermediate risk and high risk GIST patients. Thus, IA is an excellent tool for quantifying Ki-67 to predict the prognosis of GIST patients, and this semiautomated approach may be preferable for patient care.

[Soft tissue tumors : Epidemiology, classification and staging]. / Weichteiltumoren : Epidemiologie, Klassifikation und Stadieneinteilung.

Benign, intermediate and malignant soft tissue tumors can be differentiated histologically. Furthermore, the tumors can be subdivided according to their linear differentiation. In the new World Health Organization (WHO) classification of soft tissue tumors from 2013 changes have been made relating to the allocation of known entities, e. g. undifferentiated sarcomas have been formed into a new subgroup and are no longer assigned to the fibrohistiocytic tumors. The term malignant fibrous histiocytoma has been replaced by the undifferentiated sarcoma. Furthermore, two new subgroups were incorporated, the nerve sheath tumors and gastrointestinal stromal tumors. These were previously included in the tumor classification of other organ systems. These changes in the new classification are related to the rapid increase in knowledge of the genetics and the cell biology of soft tissue tumors. Malignant soft tissue tumors only represent 1% of all malignant tumors in adults. The largest subgroup of soft tissue tumors in adults is the adipocytic tumors. The liposarcoma, which belongs to this subgroup is one of the most common malignant soft tissue tumors in adults. In childhood malignant soft tissue tumors represent 15% of malignant tumors and rhabdomyosarcoma is the most common malignant soft tissue tumor.

[Comparison of modified NIH and AFIP risk-stratification criteria for gastrointestinal stromal tumors: A multicenter retrospective study].

OBJECTIVE: To evaluate and compare the value of Modified NIH criteria and AFIP criteria for the risk classification of gastrointestinal stromal tumors (GIST). METHODS: Clinicopathological and follow-up data of 539 patients diagnosed as primary GIST with or without irregular tyrosine kinase inhibitors in the Nanfang Hospital(n=143), Sun Yat-sen University Cancer Center (n=138), Guangdong Provincial People's Hospital (n=102) and Wuhan Union Hospital (n=156) from January 2012 to December 2015 were retrospectively analyzed. Recurrence risks of these 539 patients were classified by the modified NIH criteria and AFIP criteria. Overall survival and tumor-free survival of patients with different risks were compared by Log-rank test and the accuracy of the two criteria in predicting postoperative recurrence was compared by receiver operating characteristic(ROC) curves. RESULTS: Of 539 GIST patients, 283 were male and 256 were female; the age was (56.5±12.5) years old; tumors of 390 cases (72.4%) located in the stomach; tumor diameter of 178 cases (33.0%) was more than 5 cm; nuclear division number of 164 cases(30.4%) was more than 5/50 high magnification. The mean follow-up time was (37.5±13.6) months. According to the modified NIH criteria, the mean overall survival time of patients with very low, low, intermediate, and high risk was 52.0, 57.0, 56.9 and 53.6 months respectively (P=0.002), and the mean tumor-free survival time was 56.0, 58.1, 58.2 and 51.2 months respectively (P=0.000). According to the AFIP criteria, the mean overall survival time of patients with very low, low, intermediate, and high risk was 54.1, 57.8, 55.5 and 52.0 months respectively(P=0.015), and the mean tumor-free survival time was 57.3, 56.6, 54.9 and 50.4 months respectively(P=0.000). While predicting the risk of postoperative recurrence, the ROC curve of AFIP criteria has a larger area under the curve compared to the curve of the modified NIH criteria(0.689 vs 0.641, P<0.05). CONCLUSION: Compared with the modified NIH criteria, AFIP criteria predicts the risk postoperative recurrence more accurately in GIST patients.

[Clinical and morphological characteristics of gastrointestinal stromal tumors]. / Kliniko-morfologicheskaia kharakteristika gastrointestinal'nykh stromal'nykh opukholei.

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. Despite this, GISTS comprise about 2% in the structure of digestive tract cancers. They are usually localized in the stomach; however, they can be found in the small intestine and more rarely in the colon and esophagus. Although approximately 70% of the GISTs consist predominantly of spindle cells; the epithelioid cell tumors represent 20% of cases; there are also mixed variants. This variability in the morphological structure of GISTs complicates their diagnosis.

[Correlation between the CT features and malignancy risk of small (≤5 cm) gastric stromal tumors].

Objective: To evaluate the correlation between computed tomography (CT) features and malignancy risk category of small (≤5 cm) gastric stromal tumors (GST), in order to provide an image reference for preoperative assessment and intraoperative pathological diagnosis. Methods: Eighty-three patients with surgically and pathologically proven GST (≤5 cm) between January 2011 and November 2015 were recruited, and their clinical, pathological and CT data were retrospectively analyzed. According to the pathological results and malignancy risk category, the patients were divided into 2 groups, the benign biological behavior group (very low and low risk) and malignant biological behavior group (intermediate and high risk). The clinical, pathological and CT imaging findings of the two groups were analyzed. Based on the tumor diameter, the receiver operating characteristic curve (ROC) was applied to evaluate the sensitivity, specificity and the best cut-off point for distinguishing the malignancy risk between the two groups. Results: The lobulation and ulceration of the tumors presented statistically significant difference for the malignancy risk between the two groups (χ(2)=6.273 and 4.163, respectively; all P<0.05), but there was no significant difference in the sex, clinical symptoms, serum ferritin, tumor site, growth pattern, cystis degeneration and calcification (all P>0.05). No statistically significant differences were detected for the tumor CT value, arterial CT value, venous CT value, degrees of enhancement in arterial phase (DEAP), enhancement in portal venous phase (DEPP), and patient's age for distinguishing the malignancy risk between the two groups (all P>0.05). On the other hand, significant differences were found in the maximum diameter (Dmax) of tumor and the minimum diameter (Dmin) of tumor (t=-3.256 and -3.466, respectively; all P<0.05). When the cut-off point of Dmax was 1.6 cm, the area under the ROC curve, sensitivity and specificity were 0.704, 92.3% and 75.4%, respectively. When the cut-off point of Dmin was 1.5 cm, the area under the ROC curve, sensitivity and specificity were 0.713, 88.5% and 71.9%, respectively. Conclusion: CT features of the GST (≤5 cm) may predict, before surgery, the malignancy risk of small gastric stromal tumors, and provide the an image reference for preoperative assessment and intraoperative pathological diagnosis of the disease.

Cytohistological and immunohistochemical characteristics of spindle-shaped mesenchymal neoplasms occurring in the gastrointestinal tract.

The purpose of the present review is to analyze the cytohistological and immunohistochemical characteristics of spindle-shaped mesenchymal gastrointestinal neoplams (MGNs), a group of unusual neoplastic conditions with different biological behavior. These tumors exhibit clinical pictures strictly related to the site of origin and dimensions, even if they appear generally with an intramural localization. This latter point may suggest an useful application of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA), mainly followed by the cell-block procedure (CBP) in the differential diagnostic approach. First of all, we discuss the most common entity of MGNs represented by gastrointestinal stromal tumors (GISTs), analyzing the morphologic characteristics and stressing the strength of immunohistochemical algorithm for diagnostic purposes. Successively, we have reported the less common group of spindle-shaped MGNs comprehensive of those arising elsewhere the soft tissues, such as leiomyomas, leiomyosarcomas, schwannomas, inflammatory myofibroblastic tumor and intra-abdominal desmoid fibromatosis. Finally, very uncommon spindle-shaped MGNs, like clear cell, follicular dendritic cell, undifferentiated pleomorphic and radiation-induced sarcomas as well as spindle cell dedifferentiated liposarcomas, have been briefly mentioned.

Asociación de tumores del estroma gastrointestinal con otros tumores primarios. Propuesta de una nueva clasificación / Additional primary malignancies in patients with gastrointestinal stromal tumors. Proposal for a new classification

La asociación de gastrointestinal stromal tumor (GIST, «tumor del estroma gastrointestinal») con otras neoplasias primarias en un mismo paciente es un hecho no solo frecuente, sino con un interés creciente en la literatura científica. Esta asociación tiene una enorme importancia tanto por el desafío clínico, diagnóstico y terapéutico como por el impacto pronóstico que implica. En las series publicadas existe una tendencia a agrupar a estos pacientes para determinar que los GIST asociados a otras neoplasias tienen características concretas y diferenciables. Por el contrario, no existe un consenso general ni una clasificación unificada. Esta clasificación sería de gran interés, pues permitiría unificar criterios, consensuar los grupos para comparar las distintas series y demostrar si realmente la etiopatogenia subyacente a ambos tumores y las características del propio GIST varían según el tipo de que se trate. Realizamos una revisión de la literatura médica actual y una propuesta de nueva clasificación para pacientes con GIST asociados a otros tumores (AU)

Additional primary malignancies in patients with gastrointestinal stromal tumor (GIST) is not only common but of growing interest in the scientific literature. This association is of great importance in terms of clinical challenge, diagnosis and therapy as well as for the prognosis impact it implies. In the published series there is a tendency to group these patients to determine the specific and distinguishable characteristics of GIST associated with other malignancies. On the other hand, there is no general consensus or unified classification. This classification would be of great interest, as it would unify criteria, agree groups to compare different series and demonstrate whether the aetiology underlying both tumours and the GIST’s own characteristics really vary according to the type in question. We undertook a medical literature review and proposed a new classification for patients with GIST associated with other tumours (AU)

[Additional primary malignancies in patients with gastrointestinal stromal tumors. Proposal for a new classification]. / Asociación de tumores del estroma gastrointestinal con otros tumores primarios. Propuesta de una nueva clasificación.

Additional primary malignancies in patients with gastrointestinal stromal tumor (GIST) is not only common but of growing interest in the scientific literature. This association is of great importance in terms of clinical challenge, diagnosis and therapy as well as for the prognosis impact it implies. In the published series there is a tendency to group these patients to determine the specific and distinguishable characteristics of GIST associated with other malignancies. On the other hand, there is no general consensus or unified classification. This classification would be of great interest, as it would unify criteria, agree groups to compare different series and demonstrate whether the aetiology underlying both tumours and the GIST's own characteristics really vary according to the type in question. We undertook a medical literature review and proposed a new classification for patients with GIST associated with other tumours.

"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.

Tumores del estroma gastrointestinal / Gastrointestinal stromal tumors

Antecedentes: Los tumores del estroma gastrointestinal (TEG) son los tumores mesenquimales más comunes del tracto gastrointestinal (TGI), se considera que surgen de las células de Cajal, ocurren principalmente en adultos mayores (60-65 años) y se localizan en estómago (50%-70%), intestino delgado (25%-35%), colon-recto (5%-10%) y esófago (<5%). La mayoría se presenta de manera esporádica y hasta el 70% son clínicamente sintomáticos. El diagnóstico definitivo se realiza en el estudio anatomopatológico. El pronóstico de estos tumores se determina por el tamaño, recuento mitótico y localización del tumor, clasificandose: riesgo muy bajo, riesgo bajo, riesgo intermedio y riesgo alto. La cirugía es la opción terapéutica principal...

Background: Gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumors of the gastrointestinal tract (GI), areconsidered to arise from the Cajal cells. Theyoccur mainly in older adults, 60-65 years. Theypresent in the stomach (50%-70%), small intestine (25%-35%), colon and rectum (5%-10%)and esophagus (<5%). Most GISTs are sporadicand are clinically symptomatic. The definitivediagnosis is made through anatomic pathology study. To determine the prognosis of this type of tumors we use the size, mitotic count and location of the tumor, classified them in: very low risk, low risk, intermediate risk and high risk. Surgery is the main treatment...