Clinical features and prognosis of malignant small bowel tumors: Experience from a university hospital in Chile / Características clínicas y pronóstico de los tumores malignos de intestino delgado: experiencia en un hospital universitario de Chile

Background Small bowel tumors (SBT) are infrequent and represent a small proportion of digestive neoplasms. There is scarce information about SBT in Latin America.AimTo describe the epidemiology, clinical characteristics, diagnostic methods, and survival of malignant SBTs.MethodsRetrospective observational study of adult patients with histopathological diagnosis of SBT between 2007 and 2021 in a university hospital in Chile.ResultsA total of 104 patients [51.9% men; mean age 57 years] with SBT. Histological type: neuroendocrine tumor (NET) (43.7%, n=38), gastrointestinal stromal tumors (GIST) (21.8%, n=19), lymphoma (17.2%, n=15) and adenocarcinoma (AC) (11.5%, n=10). GIST was more frequent in duodenum (50%; n=12) and NET in the ileum (65.8%; n=25). Metastasis was observed in 17 cases, most commonly from colon and melanoma. Nausea and vomiting were significantly more often observed in AC (p=0.035), as well as gastrointestinal bleeding in GIST (p=0.007). The most common diagnostic tools were CT and CT enteroclysis with an elevated diagnostic yield (86% and 94% respectively). The 5-year survival of GIST, NET, lymphoma and AC were 94.7% (95%CI: 68.1–99.2), 82.2% (95%CI: 57.6–93.3), 40.0% (95%CI: 16.5–82.8) and 25.9% (95%CI: 4.5–55.7%), respectively. NET (HR 6.1; 95%CI: 2.1–17.2) and GIST (HR 24.4; 95%CI: 3.0–19.8) were independently associated with higher survival compared to AC, adjusted for age and sex.ConclusionsMalignant SBT are rare conditions and NETs are the most common histological subtype. Clinical presentation at diagnosis, location or complications may suggest a more probable diagnosis. GIST and NET are associated with better survival compared to other malignant subtypes. (AU)

Introducción Los tumores del intestino delgado (TID) son infrecuentes y la información sobre ellos es escasa en Latinoamérica.ObjetivoDescribir la epidemiología, características clínicas, métodos diagnósticos y supervivencia de los TID malignos.MétodosEstudio observacional retrospectivo de pacientes adultos con diagnóstico histopatológico de TID entre 2007-2021 en un hospital universitario de Chile.ResultadosSe observaron 104 pacientes (51,9% hombres; edad media 57 años) con TID. El tipo histológico fue tumor neuroendocrino (TNE) (43,7%, n=38), tumor estromal gastrointestinal (GIST) (21,8%, n=19), linfoma (17,2%, n=15) y adenocarcinoma (AC) (11,5%, n=10). Los GIST fueron más frecuentes en el duodeno (50%; n=12) y los TNE en el íleon (65,8%; n=25). Hubo 17 casos de metástasis, más comúnmente de colon y melanoma. Las náuseas y los vómitos se observaron con mayor frecuencia en AC (p=0,035), así como el sangrado gastrointestinal en GIST (p=0,007). Las herramientas de valoración más comunes fueron TC y enteroclisis por TC con un rendimiento diagnóstico alto (86% y 94%, respectivamente). La supervivencia a cinco años de los GIST, TNE, linfoma y AC fue 94,7% (intervalo de confianza [IC] 95%: 68,1-99,2), 82,2% (IC 95%: 57,6-93,3), 40,0% (IC 95%: 16,5-82,8) y 25,9% (IC 95%: 4,5-55,7), respectivamente. Los TNE (hazard ratio [HR] 6,1; IC 95%: 2,1-17,2) y GIST (HR 24,4; IC 95%: 3,0-19,8) se asociaron de forma independiente con una mayor supervivencia en comparación con AC, ajustado por edad y sexo.ConclusionesLos TID malignos son enfermedades poco frecuentes y los TNE son el subtipo histológico más común. La presentación clínica en el momento del diagnóstico, localización o complicaciones pueden sugerir un dictamen más probable. Los GIST y TNE se asocian a una mejor supervivencia en comparación con otros subtipos malignos. (AU)

Jejunojejunal intussusception induced by a gastrointestinal stromal tumor: a case report and literature review.

Intussusception is defined as the invagination of a proximal segment of the bowel into the adjoining or distal segment. In most adults with intussusception, there is a demonstrable lead point with a definite pathologic abnormality. The clinical features of intussusception include chronic intermittent abdominal pain, nausea and vomiting, constipation, and a palpable abdominal mass. The present case report describes a 62-year-old woman with a 2-week history of abdominal pain and 9-day history of vomiting. Clinical, imaging, and histologic evaluations revealed a jejunojejunal intussusception with a gastrointestinal stromal tumor as the lead point. A gastrointestinal stromal tumor should be considered as a possible lead point in adult patients with intussusception. The implication of reducing the intussusception prior to tumor resection requires further evaluation in view of the risk of venous embolism, including direct spread of malignant cells, in cases involving a large polypoid mass with a necrotic surface that extends to the serosa as shown by intraoperative examination. Accordingly, the rationale for adjuvant therapy with imatinib also requires further evaluation.

Characteristics of gastrointestinal stromal tumors associated to other tumors / Características de los tumores del estroma gastrointestinal asociados a otras neoplasias

Introduction: Our aim is to analyze the differences between sporadic gastrointestinal stromal tumors and those associated with other tumors. Methods: Retrospective cohort study including patients with diagnosis of gastrointestinal stromal tumors operated at our center. Patients were divided into two groups, according to whether or not they had associated other tumors, both synchronously and metachronously. Disease free survival and overall survival were calculated for both groups. Results: 96 patients were included, 60 (62.5%) were male, with a median age of 66.8 years (35–84). An association with other tumors was found in 33 cases (34.3%); 12 were synchronous (36.3%) and 21 metachronous (63.7%). The presence of mutations in associated tumors was 70% and in non-associated tumors 75%. Associated tumors were classified as low risk tumors based on Fletcher's stratification scale (p=0.001) as they usually were smaller in size and had less than ≤5 mitosis per 50 HPF compared to non-associated tumors. When analyzing overall survival, there were statistically significant differences (p=0.035) between both groups. Conclusion: The relatively high proportion of gastrointestinal stromal tumors cases with associated tumors suggests the need to carry out a study to rule out presence of a second neoplasm and a long-term follow-up should be carried out in order to diagnose a possible second neoplasm. Gastrointestinal stromal tumors associated with other tumors have usually low risk of recurrence with a good long-term prognosis.(AU)

Introducción: El objetivo de este estudio es analizar si existen diferencias entre los GIST esporádicos y los que se presentan asociados a otros tumores. Métodos: Estudio de cohorte retrospectivo de pacientes operados de tumores del estroma gastrointestinal (GIST) en nuestro centro. Se dividió a los pacientes en función de si presentaban otros tumores asociados o no, de forma sincrónica o metacrónica. La supervivencia libre de enfermedad y la supervivencia global se calcularon en ambos grupos. Resultados: Se incluyeron un total de 96 pacientes, 60 (62,5%) eran hombres con una media de edad de 66,8 años (35-84). Se encontró una asociación con otros tumores en 33 casos (34,3%); 12 de manera sincrónica (36,3%) y 21 metacrónica (63,7%). La presencia de mutaciones en el grupo de tumores asociados fue de 70% y en el de no asociados de 75%. Los tumores asociados se clasificaron como tumores de bajo riesgo según la escala de Fletcher (p = 0,001), ya que fueron de menor tamaño y presentaron menos de ≤ 5 mitosis por 50 HPF en comparación con los no asociados. Al analizar la supervivencia global, hubo diferencias estadísticamente significativas entre ambos grupos (p = 0,035). Conclusión: La proporción relativamente alta de casos de GIST con tumores asociados sugiere la necesidad de realizar un estudio para descartar la presencia de una segunda neoplasia y, tras el tratamiento de GIST, elaborar un seguimiento a largo plazo para diagnosticar una posible segunda neoplasia. Los GIST asociados a otros tumores suelen tener un riesgo bajo de recurrencia con un buen pronóstico a largo plazo.(AU)

A case report of abdominal metastatic dermatofibrosarcoma protuberans misdiagnosed as gastrointestinal stromal tumor.

Dermatofibrosarcoma protuberans (DFSP) is a low-grade malignant soft-tissue tumor that originates from the skin. It has a slow onset in the early stages, non-specific clinical symptoms, low specificity, and can easily be overlooked, missed, or misdiagnosed by clinicians and pathologists. In addition, DFSP is prone to recurrence after local surgical treatment; however, distant metastasis, especially abdominal metastasis, is rare, which is also a challenge for the accurate diagnosis of DFSP when it progresses distantly. Now a case of abdominal metastasis of DFSP is reported. The patient has been treated with imatinib for ten years, and the lesion has shrunk, but because the patient has been receiving imatinib treatment, his abdominal lesion was once misdiagnosed as gastrointestinal stromal tumor. Therefore, we report on this case to enhance the understanding of the diagnosis and treatment of DFSP, and to provide reference for the pathological diagnosis and precise treatment of such patients.

Clinical features and prognosis of malignant small bowel tumors: Experience from a university hospital in Chile.

BACKGROUND: Small bowel tumors (SBT) are infrequent and represent a small proportion of digestive neoplasms. There is scarce information about SBT in Latin America. AIM: To describe the epidemiology, clinical characteristics, diagnostic methods, and survival of malignant SBTs. METHODS: Retrospective observational study of adult patients with histopathological diagnosis of SBT between 2007 and 2021 in a university hospital in Chile. RESULTS: A total of 104 patients [51.9% men; mean age 57 years] with SBT. Histological type: neuroendocrine tumor (NET) (43.7%, n=38), gastrointestinal stromal tumors (GIST) (21.8%, n=19), lymphoma (17.2%, n=15) and adenocarcinoma (AC) (11.5%, n=10). GIST was more frequent in duodenum (50%; n=12) and NET in the ileum (65.8%; n=25). Metastasis was observed in 17 cases, most commonly from colon and melanoma. Nausea and vomiting were significantly more often observed in AC (p=0.035), as well as gastrointestinal bleeding in GIST (p=0.007). The most common diagnostic tools were CT and CT enteroclysis with an elevated diagnostic yield (86% and 94% respectively). The 5-year survival of GIST, NET, lymphoma and AC were 94.7% (95%CI: 68.1-99.2), 82.2% (95%CI: 57.6-93.3), 40.0% (95%CI: 16.5-82.8) and 25.9% (95%CI: 4.5-55.7%), respectively. NET (HR 6.1; 95%CI: 2.1-17.2) and GIST (HR 24.4; 95%CI: 3.0-19.8) were independently associated with higher survival compared to AC, adjusted for age and sex. CONCLUSIONS: Malignant SBT are rare conditions and NETs are the most common histological subtype. Clinical presentation at diagnosis, location or complications may suggest a more probable diagnosis. GIST and NET are associated with better survival compared to other malignant subtypes.

Colonic gastrointestinal stromal tumor (GIST) presenting with colocolonic intussusception: A rare case report.

An 8-year-old spayed female British bulldog was presented with vomiting, hyporexia, and large-bowel diarrhea. Abdominal ultrasound revealed a focal colonic mass with an intussusception located immediately oral to the mass. The intussusception encompassed the ascending and transverse colon and was non-reducible. Colonic resection and anastomosis were completed to include the intussusception and colonic mass. Histopathological examination of the mass demonstrated a spindle cell neoplasm arising within the muscular wall of the intussuscepted segment that obliterated normal architecture. Mild-to-moderate cytoplasmic immunoreactivity of the tumor cell population for CD117 and smooth muscle actin was consistent with a diagnosis of a gastrointestinal stromal tumor. The dog described herein remains alive and free of progressive disease at the time of writing. Key clinical message: The entire gastrointestinal tract should be evaluated in any animal with gastrointestinal symptoms. A gastrointestinal stromal tumor remains a plausible differential diagnosis, regardless of the intestinal segment affected, and tumorassociated intussusception is a rare but urgent clinical finding.

Tumeur stromale gastro-intestinale du côlon (GIST) présentant une invagination colocolique : un rapport de cas rare. Une femelle bouledogue anglais stérilisée de 8 ans a présenté des vomissements, une hyporexie et une diarrhée d'origine du gros intestin. L'échographie abdominale a révélé une masse colique focale avec une invagination située immédiatement oralement à la masse. L'intussusception englobait le côlon ascendant et transverse et était non réductible. La résection colique et l'anastomose ont été réalisées pour inclure l'intussusception et la masse colique. L'examen histopathologique de la masse a révélé un néoplasme à cellules fusiformes apparaissant dans la paroi musculaire du segment invaginé qui a oblitéré l'architecture normale. L'immunoréactivité cytoplasmique légère à modérée de la population de cellules tumorales pour le CD117 et l'actine des muscles lisses étaient compatibles avec un diagnostic de tumeur stromale gastro-intestinale. Le chien décrit ici est toujours vivant et exempt de maladie évolutive au moment de la rédaction.Message clinique clé :L'ensemble du tractus gastro-intestinal doit être évalué chez tout animal présentant des symptômes gastrointestinaux. Une tumeur stromale gastro-intestinale reste un diagnostic différentiel plausible, quel que soit le segment intestinal atteint, et l'intussusception associée à la tumeur est une constatation clinique rare mais urgente.(Traduit par Dr Serge Messier).

Sarco/endoplasmic reticulum calcium ATPase 3 (SERCA3) expression in gastrointestinal stromal tumours.

Accurate characterisation of gastrointestinal stromal tumours (GIST) is important for prognosis and the choice of targeted therapies. Histologically the diagnosis relies on positive immunostaining of tumours for KIT (CD117) and DOG1. Here we report that GISTs also abundantly express the type 3 Sarco/Endoplasmic Reticulum Calcium ATPase (SERCA3). SERCA enzymes transport calcium ions from the cytosol into the endoplasmic reticulum and play an important role in regulating the intensity and the periodicity of calcium-induced cell activation. GISTs from various localisations, histological and molecular subtypes or risk categories were intensely immunopositive for SERCA3 with the exception of PDGFRA-mutated cases where expression was high or moderate. Strong SERCA3 expression was observed also in normal and hyperplastic interstitial cells of Cajal. Decreased SERCA3 expression in GIST was exceptionally observed in a zonal pattern, where CD117 staining was similarly decreased, reflecting clonal heterogeneity. In contrast to GIST, SERCA3 immunostaining of spindle cell tumours and other gastrointestinal tumours resembling GIST was negative or weak. In conclusion, SERCA3 immunohistochemistry may be useful for the diagnosis of GIST with high confidence, when used as a third marker in parallel with KIT and DOG1. Moreover, SERCA3 immunopositivity may be particularly helpful in cases with negative or weak KIT or DOG1 staining, a situation that may be encountered de novo, or during the spontaneous or therapy-induced clonal evolution of GIST.

Genomic profiling in GIST: Implications in clinical outcome and future challenges.

Gastrointestinal Stromal Tumors (GIST) are the most frequent mesenchymal neoplasia of the digestive tract. Genomic alterations in KIT, PDFGRA, SDH, and BRAF genes are essential in GIST oncogenesis. Therefore, the mutations in these genes have demonstrated clinical implications. Tumors with deletions in KIT-exon 11 or duplications in exon 9 are associated with a worse prognosis. In contrast, KIT-exon 11 substitutions and duplications are associated with a better clinical outcome. Moreover, mutations in Kit exon 9 and 11 are actionable, due to their response to imatinib, while mutations in PDGFRA respond to sunitinib and/or avapritinib. Although, molecular testing on tissue samples is effective; it is invasive, requires adequate amounts of tissue, and a long experimental process is needed for results. In contrast, liquid biopsy has been proposed as a simple and non-invasive method to test biomarkers in cancer. The most common molecule analyzed by liquid biopsy is circulating tumor DNA (ctDNA). GISTs ctDNA testing has been demonstrated to be effective in identifying known and novel KIT mutations that were not detected using traditional tissue DNA testing and have been useful in determining progression risk and response to TKI therapy. This allows the clinician to have an accurate picture of the genetic changes of the tumor over time. In this work, we aimed to discuss the implications of mutational testing in clinical outcomes, the methods to test ctDNA and the future challenges in the establishment of alternatives of personalized medicine.

Primary EGIST of the greater omentum - a rare presentation.

Extragastrointestinal stromal tumors (EGISTs) are rare mesenchymal neoplasms, which develop in the retroperitoneum, mesentery, and omentum, lacking continuity to the stomach or intestines. Authors hereby present a female patient with a large heterogeneous abdominal mass as a case of an omental EGIST. A 46-year-old woman was referred to our hospital due to an insidious enlargement and colicky pain in the right iliac fossa. Abdominal palpation revealed a voluminous, freely mobile, and non-pulsatile mesoabdominal bulge expanding to the hypogastrium. On exploratory midline laparotomy, the tumor was densely fused to the greater omentum, not connected to the stomach, without gross involvement of adjacent structures. The large mass was completely excised after adequate mobilization. Immunohistochemical techniques showed strong and diffuse expression of WT1, actin and DOG-1, as well as multifocal c-KIT marking. Mutational study concluded a double mutation of KIT exon 9 and a mutation of PDGFRA exon 18. The patient was submitted to adjuvant treatment with imatinib mesylate 800 mg/day. Despite an extremely diverse presentation, omental EGISTs often remain clinically silent for a long time having enough space to grow before becoming symptomatic. These tumors have a consistent pattern of metastasis that typically spares lymph nodes unlike epithelial gut neoplasms. Surgery remains the preferred treatment for non-metastatic EGISTs of the greater omentum. It is possible that DOG-1 will supplant KIT as the leading marker in the future. The scarcity of knowledge on omental EGISTs implies a close monitoring of these patients to detect local relapse or distant metastasis.

Malignant Gastrointestinal Neuroectodermal Tumor of Small Intestine Showing DOG1 Expression: A Case Report and Review of Literature.

Malignant gastrointestinal neuroectodermal tumor (GNET), also referred to as clear cell sarcoma-like tumor of the GI tract is a rare mesenchymal tumor of the gastrointestinal tract. It has to be distinguished from various mimickers including gastrointestinal stromal tumor (GIST) due to its aggressive course and different natural history and therapeutic approach. Here we report a case of GNET arising in the small intestine with aberrant DOG1 expression posing a diagnostic challenge. In this context, the combination of clinical, histomorphological, immunohistochemical, and molecular features helped to establish a proper diagnosis.

Gastrointestinal stromal tumour in a jejunal diverticulum: The eighth reported case worldwide with a brief review of the literature.

Jejunal diverticulosis is uncommon and so are gastrointestinal stromal tumours (GIST) arising in the jejunum. GIST arising in a jejunal diverticulum is a rarity and to date there are only 7 cases in the English literature. Our case of GIST occurring in a jejunal diverticulum of a 48-year-old lady would be the first reported in Malaysia and the 8th in the world. As in most cases, the clinical presentation and radiological findings of this patient were non-specific. With a history of acute abdominal pain, vomiting and fever, the patient was provisionally diagnosed as a case of twisted ovarian cyst and subjected to laparotomy. An intact roundish jejunal diverticulum 5.0 cm x 5.0 cm, about 50 cm distal to the duodeno-jejunal junction was found and resected with a segment of small intestine. Microscopic examination showed a tumour of the cut open diverticular wall, with epithelioid to spindled cells, demonstrating a mitotic rate of 1-2 per 5 mm2, confined to, while infiltrating the wall of the diverticulum. The immunohistochemical profile of positive staining for CD117, DOG-1, smooth muscle actin and CD34, and negative expression of desmin and S100 protein, clinched the diagnosis of GIST. Based on the AFIP Criteria for risk stratification,1 the patient was categorised as having moderate risk for disease progression, and was not offered further targeted imatinib as an immediate measure. The patient has remained well at the time of writing i.e. 8 months following excision, and continues on active surveillance by the surgical and oncological teams, with the option of imatinib, should the necessity arise. This case is presented not merely for the sake of documenting its rarity, but as a reminder to stay alert for uncommon conditions in histopathology practice.

Gastrointestinal stromal tumor in North Africa and the middle east: updates in presentation and management from an 11-year retrospective cohort.

OBJECTIVES: This study described the epidemiological, clinical, and survival profiles of patients with gastrointestinal stromal tumor (GIST) in North Africa and the Middle East (AfME). METHODS: This regional, multicenter, observational, retrospective study collected 11-year data on demographics, medical history, disease characteristics, current treatment approaches of GIST, the safety of the most common tyrosine kinase inhibitors (TKIs), second cancers, and survival status. RESULTS: Data of 201 eligible patients were analyzed: mean age was 56.9 ± 12.6 years; 111 (55.2%) patients were men, 21 (10.4%) patients had previous personal malignancy. The most common clinical presentation of GIST was dysphagia [92 (45.8%) patients]. The stomach was the most common primary site in 120 (60.7%) patients, 171 (85.1%) patients had localized disease at diagnosis. 198 (98.5%) GIST cases were CD117/CD34-positive. Imatinib was used in the neoadjuvant (18/21 patients), adjuvant (85/89 patients), and first-line metastatic treatment (28/33 patients) settings. The most common non-hematological toxicity associated with TKIs was vomiting in 32/85 (37.6%) patients. Overall, 100 (49.8%) patients (95%CI: 42.8-56.7%) were alive and disease-free while 30 (14.9%) patients were alive with active disease. CONCLUSION: Presentation of GIST in our AfME population is consistent with global reports, being more frequent in patients >50 years old and having the stomach as the most common primary site. Unlike what is usually reported, though, we did have more patients with lymphatic spread of the disease. Despite the global trend and advances in the treatment of GIST according to molecular profile, this is still far to happen in our population given the lack of access to molecular profiles and the high associated cost.

Longitudinal Natural History Study of Children and Adults with Rare Solid Tumors: Initial Results for First 200 Participants.

Understanding of tumor biology and identification of effective therapies is lacking for many rare tumors. My Pediatric and Adult Rare Tumor (MyPART) network was established to engage patients, advocates, and researchers and conduct a comprehensive longitudinal Natural History Study of Rare Solid Tumors. Through remote or in-person enrollment at the NIH Clinical Center, participants with rare solid tumors ≥4 weeks old complete standardized medical and family history forms, patient reported outcomes, and provide tumor, blood and/or saliva samples. Medical records are extracted for clinical status and treatment history, and tumors undergo genomic analysis. A total of 200 participants (65% female, 35% male, median age at diagnosis 43 years, range = 2-77) enrolled from 46 U.S. states and nine other countries (46% remote, 55% in-person). Frequent diagnoses were neuroendocrine neoplasms (NEN), adrenocortical carcinomas (ACC), medullary thyroid carcinomas (MTC), succinate dehydrogenase (SDH)-deficient gastrointestinal stromal tumors (sdGIST), and chordomas. At enrollment, median years since diagnosis was 3.5 (range = 0-36.6), 63% participants had metastatic disease and 20% had no evidence of disease. Pathogenic germline and tumor mutations included SDHA/B/C (sdGIST), RET (MTC), TP53 and CTNNB1 (ACC), MEN1 (NEN), and SMARCB1 (poorly-differentiated chordoma). Clinically significant anxiety was observed in 20%-35% of adults. Enrollment of participants and comprehensive data collection were feasible. Remote enrollment was critical during the COVID-19 pandemic. Over 30 patients were enrolled with ACC, NEN, and sdGIST, allowing for clinical/genomic analyses across tumors. Longitudinal follow-up and expansion of cohorts are ongoing to advance understanding of disease course and establish external controls for interventional trials. SIGNIFICANCE: This study demonstrates that comprehensive, tumor-agnostic data and biospecimen collection is feasible to characterize different rare tumors, and speed progress in research. The findings will be foundational to developing external controls groups for single-arm interventional trials, where randomized control trials cannot be conducted because of small patient populations.

CLINICOPATHOLOGICAL AND IMMUNO-HISTOCHEMICAL CHARACTERIZATION OF GASTROINTESTINAL STROMAL TUMOUR AT FOUR TERTIARY HEALTH CENTERS IN NIGERIA USING CD117, DOG1, AND HER-2 BIOMARKERS.

Introduction: Gastrointestinal stromal tumours (GISTs) are neoplastic lesions that primarily affect the digestive tract and develop from interstitial cells of Cajal. Due to their malignant potential and personalized treatment, these lesions require histopathologic and immunohistochemical characterization. In this investigation, the sex, age, lesional sites of origin, histopathologic types, the prevalence of HER-2 expression, prognostic indices (based on tumour size and mitotic figures), expression of CD117 and DOG1, and characteristics of patients with GIST were all characterized. Methodology: This is a retrospective cross-sectional analysis of GIST cases seen at four tertiary healthcare centers in Nigeria over ten years (2008 to 2017) and investigated utilizing histopathological and immunohistochemical (CD117, DOG1, and HER-2) methods. Result: In this study, there were twenty GIST cases. Notably, the majority (40%) of the cases had tumours with sizes between 7.0 and 8.0, the stomach was the most frequent site (70%) and the spindle cell type of GIST was the most prevalent (80%) histopathological type. Additionally, the stomach was significantly associated with GIST as an origin site (with a P value of 0.001), and 100% and 50% of these tumours were immunoreactive with CD117 and DOG1 respectively. Finally, HER-2 immunoreactivity was negatively stained with GIST tumour. Conclusion: In our study, GISTs most frequently develop in the stomach, and CD117& DOG1 are essential for correctly diagnosing these tumours. However, HER-2 immunoreactivity is a predictive marker of survival for personalized care.

Synchronous and metachronous neoplasms of different histogenesis with gastrointestinal stromal tumor (GIST): 10 years experience of a single institution.

AIM: Gastrointestinal stromal tumors (GISTs) are the most common primary mesenchymal neoplasms of the gastrointestinal tract. Significant advances have been made in its pathogenesis, diagnosis, and treatment over the past few decades. However, little is known about the occurrence of synchronous or methacronous tumors with other histogenesis in addition to GISTs. The aim of this study was to present a series of 15 patients diagnosed with a second primary neoplasm in addition to GIST. MATERIAL AND METHODS: Patients who were diagnosed with both GIST and other primary neoplasm between January 2010 and December 2019 were included in the study. Demographic, clinicopathologic and immunohistochemical parameters of the patients were analyzed along with the follow-up results RESULTS: This study included 12 men and 3 women with a median age of 68 years (range: 57-83 years). Of the GISTs, 93.3% were localized in the stomach and 73.3% were at very low / low risk category. Of the second primary tumors, 66.6% were in the gastrointestinal tract. Detection of the GIST was synchronous in 9 cases, metachronous in 2 cases and preceded the GIST diagnosis in 4 cases. GIST was incidentally found intra-operatively in 3 of the cases. The mean size of the synchronous GISTs was 20 mm while the most common GIST-associated malignancy was gastric adenocarcinoma. The median follow-up times was 62 months (range: 13-129 months). CONCLUSIONS: The prevalence of secondary malignancies in GIST patients is significantly higher than the healthy population. The high occurrence rate of additional primary tumors in GIST patients has focused the attention of surgeons on this problem. While it is not yet clear if there is a causal association or a common genetic mechanism for the concomitant occurrence of GIST with other malignancies, a closer surveillance of GIST patients is needed due to their proved increased prevalence of a second primary tumor especially during the first year after diagnosis. KEY WORDS: Gastrointestinal stromal tumor, Coexistence, Synchronous malignancy, Second neoplasm, Gastric adenocarcinoma.