BRAFV600E and KIT immunoexpression in early-stage melanoma

Abstract: Melanoma is widely known as the most lethal skin cancer. Specific tumor-related mortality can be significantly reduced if diagnosis and treatment are properly performed during initial phases of the disease. The current search for biomarkers in early-stage melanomas is a high-priority challenge for physicians and researchers. We aimed to assess the immunoexpression of BRAFV600E and KIT in a case series consisting of 44 early-stage melanomas. Formalin-fixed paraffin-embedded samples were systematically evaluated using a semi-quantitative method based on scores of percentage and intensity for immunostained tumor cells. We observed significant concordance between BRAFV600E and KIT immunoexpression in thin invasive melanomas. Our findings corroborate previous evidence showing abnormal expression of proteins associated with MAPK intracellular signaling pathway in early-stage melanomas.

Evaluation of the relationship between c-Kit expression and mean platelet volume in classic Kaposi's sarcoma

Abstract: Background: c-Kit is a proto-oncogene that encodes tyrosine kinase receptor (CD117). Mean platelet volume (MPV) is a useful marker, providing information on platelet function and diameter. Objective: To investigate c-Kit expression and intensity in patients with Kaposi's sarcoma (KS) and to investigate the relation between Ki-67 proliferation and MPV. Methods: A total of 32 patients, diagnosed with classic cutaneous KS, were included in this study. We reevaluated the histopathological reports with the preparations, confirmed the diagnosis and then determined the patients' histopathological stages. c-Kit expression and Ki-67 proliferation were investigated immunohistochemically in KS cases, while MPV in all cases was checked. Results: Although c-Kit expression was detected in 22 cases (68.8%), it was not expressed in 10 cases (31.2%). We detected 8 cases with + (25%), 6 with ++ (18.8%) and 8 with +++ (25%). Ki-67 expression was 5.0% (min-max 1.0-20.0). Relapse was observed in 5 cases (15.6%) out of 32. There was positive correlation between c-Kit expression and MPV (rs=0.598, p<0.001), and between c-Kit intensity and MPV (rs=0.588, p<0.001). Conclusion: c-Kit is highly positive in KS. c-Kit positivity indicates a high risk of tumor growth, invasion and relapse. Furthermore, c-Kit expression stimulates megakaryocytes to release young and large thrombocytes into the periphery. Thus, high MPV, c-Kit expression and immunostaining intensity indicate high invasion and relapse in KS subjects.

Malignant acanthosis nigricans in a patient with a gastrointestinal stromal tumor

No abstract available.

Tumor del estroma gastrointestinal (TEGI): un estudio de su frecuencia y perfil de inmunohistoquímica / Gastrointestinal stromal tumors: analysis of 51 cases, immunohistochemical expression

Background: Gastrointestinal Stromal Tumors (GIST) have a mesenchymal origin and correspond to 1 percent of all gastrointestinal tumors. They have a benign behavior in approximately 75 percent of cases. They express CD117, CD34, smooth muscle actin, S-100 and desmin, markers that are useful in the differential diagnosis of smooth muscle tumors and those of neurogenic origin. Aim: To report our experience with GIST. Material and Methods: A retrospective, observational study. The pathology reports of GIST in the period 2004-2008 were reviewed. Immunohistochemical expression, pathological grade, mitotic index and histological patterns were reviewed. The medical records of patients were reviewed to obtain age and gender, location, size and presence of metastases. Results: A total of 51 GIST were identified, coming from 21 males and 30 females. Nineteen tumors were located in the small bowel, 18 in the stomach, four in the rectum, two in the colon and in five, the location was not specified. In 28 cases, the pathological pattern was spindle cell, in 12 mixed, in six epithelioid, in three pleomorphic, in one signet ring cell and giant cell in one. Forty nine percent of tumors were of high grade. Metastases were found in the liver in two cases, in the omentum in two and in the spleen, kidney, retroperitoneum and pancreas, in one case each. Two had lymph node involvement. Conclusions: GIST tumor corresponded to a 0.12 percent of all pathology reports during the study period. Most tumors in this series were of high grade.

Introducción: Los Tumores del Estroma Gastrointestinal (TEGI) son de origen mesenquimal comprendiendo el 1 por ciento de todos los tumores GI. Son benignos del 70 a 80 por ciento. Expresan CD117, CD34, actina de músculo liso, S-100 y desmina, marcadores útiles en el diagnóstico diferencial de tumores de músculo liso y tumores de origen neurogénico. Material y Método: Es un estudio retrospectivo y descriptivo. Se revisaron los reportes en el período 2004-2008 registrados como TEGI, valorando la expresión Inmunohistoquímica, grado histológico, índice mitótico, y patrones histológicos. Del reporte histológico se obtuvo la edad y sexo del paciente, localización, tamaño y metástasis. Resultados: Se recolectaron 51 casos corroborados como TEGI. Encontrando una prevalencia del sexo femenino (30) y una edad media de 52 años. Las localizaciones fueron: Intestino delgado (19), estómago (18), no especificado (5), recto (4), colon (2), retroperitoneo (2), no encontramos en esófago. Los patrones encontrados fueron el fusocelular (28), mixto (12), epitelioide (6), pleomórfico (3), células en anillo de sello (1), células gigantes (1). La mayoría (49 por ciento) fue de alto grado, presentando metástasis a hígado (2), ganglios (2), epiplón (2), bazo (1), riñón (1), retroperitoneo (1) y páncreas (1). Discusión: Se realizaron un total de 41.035 estudios histopatológicos, de los cuales 51 casos corresponden a LEGI, esto equivale al 0,12 por ciento. Encontramos tumores en los que su morfología, tamaño e índice mitótico fueron de bajo grado y presentaron metástasis y recidivas al momento del diagnóstico. Veinticinco casos fueron de alto grado (49 por ciento), lo cual es mayor a lo reportado por la literatura 20-30 por ciento, probablemente porque este es un hospital de concentración y generalmente los pacientes acuden a atención médica en una etapa avanzada de la enfermedad.

Mast cells in basal cell carcinoma

Many researchers have been more interested in inflammatory changes in tumor stroma recently. Recent studies have shown that mast cells are significantly increased in human skin basal cell carcinoma [BCC] and are associated with tumor aggressiveness. In this study, we compared the number of mast cell population expressing c-kit in the BCC samples and normal skin. We also evaluated the number of this cell type in infliltrative and noninfiltrative subtypes of this tumor. Tissue sections containing 30 cases of BCCs and 30 normal skins were prepared and after staining with c-kit were analyzed for the number of stromal mast cells. Our results indicate that the number of c-kit positive mast cells was significantly higher in BCC when compared with normal skin [P<0.01], and number of mast cells in the stroma of infiltrative subtypes of this tumor is higher than noninfiltrative subtypes [p<0.04]. In our study there wasn't any correlation between sex and age with mast cells count. Our results are in line with previous studies indicating that mast cell numbers are increased in BCC. In addition, the results suggest that mast cell populations may contribute to BCC progression. Besides, we demonstrated that this increase in mast cell density was independent of the patient's ages and sexes

Adenocarcinoma gástrico primario concomitante con tumor estromal gastrointestinal: Reporte de un caso y revisión de literatura / Concomitant presence of a gastric adenocarcinoma and gastrointestinal stromal tumor: Report of one case

The concomitant presence of a primary gastric adenocarcinoma and a gastrointestinal stromal tumor in the stomach is uncommon. We report a 68-year-old male with an advanced gastric adenocarcinoma. During gastrectomy, a nodular intramural lesion was found. The pathological study, revealed a gastrointestinal stromal tumor, positive form CD117. After six months of follow up, there is no evidence of recurrence of either tumor.

Is the positive c-kit immunostaining associated with the presence of cells analogous to the intersticial cells of Cajal in the ciliary muscle? / A imunomarcação positiva para c-kit está associada com a presença de células análogas às intersticiais de Cajal no músculo ciliar?

PURPOSE: Interstitial cells of Cajal were identified in the gastrointestinal tract of several species, with close relation to the enteric nervous system. Since it was recognized that interstitial cells of Cajal express the gene product of c-kit, we performed immunohistochemistry for c-kit protein in ciliary muscle specimens of monkeys' eyes. METHODS: Eight eyes from four adult male new world monkeys (Cebus apella) were studied. After blocking endogenous peroxidase activity and nonspecific protein binding, 1:100 dilution of mouse monoclonal antibody against c-kit human oncoprotein was applied to tissues. Antigen-antibody reaction was visualized using the avidin-biotinylated horseradish peroxidase complex in each slide. RESULTS: We observed some groups of fusiform c-kit expressing cells located amongst muscle bundles of the ciliary muscle. Other pigment cells and mast cells were also observed. CONCLUSION: C-kit expressing cells observed in the ciliary muscle of Cebus apella, showed no similarity to melanocytes or mast cells and they could be associated with their gastrointestinal interstitial cells of Cajal counterpart.

OBJETIVO: As células intersticiais de Cajal estão presentes no trato gastrintestinal de diversas espécies animais, em íntima relação com o sistema nervoso entérico. Uma vez que as células intersticiais de Cajal expressam o produto do gene c-kit, realizou-se um ensaio imuno-histoquímico a fim de se verificar a marcação da proteína c-kit no músculo ciliar de amostras de olhos de macacos. MÉTODOS: Oito olhos de quatro macacos do novo mundo (Cebus apella) foram estudados. Após bloqueio da peroxidase endógena e de ligação protéica não específica, os tecidos receberam aplicação de anticorpos de camundongos antioncoproteína c-kit humana (1:100). A reação antígeno-anticorpo foi verificada através da aplicação do complexo avidina-biotinilada-peroxidase em cada lâmina. RESULTADOS: Foram observados grupos de células que expressam c-kit, localizadas entre as fibras do músculo ciliar. Mastócitos e outras células pigmentadas também foram observadas. CONCLUSÃO: Algumas células que expressam c-kit, observadas no músculo ciliar de Cebus apella, não mostraram similaridade com mastócitos ou melanócitos e podem ser classificadas como análogas das células intersticiais de Cajal gastrintestinais.

CD34-positive cells and their subpopulations characterized by flow cytometry analyses on the bone marrow of healthy allogenic donors / Células CD34-positivas e suas subpopulações caracterizadas por análise de citometria de fluxo em doadores para transplante alogênico de medula óssea

CONTEXT AND OBJECTIVE: Counting and separating hematopoietic stem cells from different sources has importance for research and clinical assays. Our aims here were to characterize and quantify hematopoietic cell populations in marrow donors and to evaluate CD34 expression and relate this to engraftment. DESIGN AND SETTING: Cross-sectional study on hematopoietic stem cell assays, using flow cytometry on donor bone marrow samples, for allogenic transplantation patients at two hospitals in São Paulo. METHODS: Immunophenotyping of marrow cells was performed in accordance with positive findings of CD34FITC, CD117PE, CD38PE, CD7FITC, CD33PE, CD10FITC, CD19PE, CD14FITC, CD13PE, CD11cPE, CD15FITIC, CD22PE, CD61FITC and CD56PE monoclonal antibodies in CD45PerCP+ cells, searching for differentiation and maturation regions. CD34+ sorting cells were analyzed for CD38 and CD117. Rh-123 retention was done before and after sorting. Antigen expression and CD34+ cells were correlated with engraftment. RESULTS: In region R1, 0.1 percent to 2.8 percent of cells were CD34+/CD45+ and 1.1 percent, CD34+/CD45-. The main coexpressions of CD45+ cells were CD38, CD22, CD19 and CD56 in R2 and CD33, CD11c, CD14, CD15 and CD61 in R3 and R4. After sorting, 2.2x10(6) CD34+ cells were equivalent to 4.9 percent of total cells. Coexpression of CD34+/CD38+ and CD34+/CD117+ occurred in 94.9 percent and 82 percent of events, respectively. There was a positive relationship between CD34+ cells and engraftment. More than 80 percent of marrow cells expressed high Rh-123. CD34+ cell sorting showed that cells in regions of more differentiated lineages retained Rh-123 more intensively than in primitive lineage regions. CONCLUSION: We advocate that true stem cells are CD34+/CD45-/CD38-/low-Rh-123 accumulations.

CONTEXTO E OBJETIVO: A contagem e separação de células-tronco hematopoéticas de diferentes fontes tem importância para ensaios clínicos e pesquisa basica. Nosso objetivo foi caracterizar e quantificar as populacões de células hematopoéticas, bem como avaliar a expressão do antígeno CD34 em populações mais primitivas e correlacioná-las com a enxertia nos doadores de medula óssea para transplante alogênico. TIPO DE ESTUDO E LOCAL: Estudo transversal no qual a diferenciação e a seleção de células-tronco hematopoéticas foram realizadas em amostras de medula óssea de doadores de pacientes submetidos a transplante alogênico nos Hospitais São Paulo e Santa Marcelina, São Paulo, Brasil. MÉTODOS: Imunofenotipagem de células mononucleares de medula óssea foi feita na população de células CD45PerCP+ com os seguintes anticorpos: CD34FITC, CD117PE, CD38PE, CD7FITC, CD33PE, CD10FITC, CD19PE, CD14FITC, CD13PE, CD11cPE, CD15FITC, CD22PE, CD61FITC e CD56PE. Após a definição de regiões de células positivas ao CD34, estas células foram selecionadas e analisadas para a co-expressão do CD38 e CD117. Células mononucleares totais de medula óssea e aquelas obtidas após a seleção foram testadas para a retenção de Rh-123. O teste de Friedman e o coeficiente de Sperman foram utilizados para comparar as expressões e correlacionar a contagem de células CD34+ com a enxertia. RESULTADOS: Na região R1, 0,1 por cento a 2,8 por cento das células foram CD34+/CD45+, porém apenas 1,1 por cento das células foram CD34+/CD45-. As principais co-expressões de células CD45+ foram CD38, CD22, CD19 e CD56 na região R2 e CD33, CD11c, CD14, CD15 e CD61 nas regiões R3 e R4. Após a seleção, a mediana de 2,2x106 células CD34+ foi equivalente a 4,9 por cento do total mediano de células da medula óssea. Co-expressões de células CD34+/CD38+ e CD34+/CD117+ ocorreram em 94,95 e 82 por cento, respectivamente. Houve relação positiva entre o número de células CD34+ infundidas e o dia da enxertia. ...

Histological and functional organization in human testicle: expression of receptors c-kit and androgens / Organización histológica y funcional en el testículo humano: expresión de los receptores c-kit y andrógenos

The objective of this work was identify the presence of interstitial cells of Cajal, muscle cells, nerves and androgen receptor positive cells in adult human testicle, using immunohistochemical detection for c-kit/CD-117, actin smooth muscle specific (ASMS), neurofilament (N) and androgen receptor (AR), respectively. The samples were obtained from patients (n= 10) with diagnosis of prostate cancer, with surgery of orchiectomy. Subsequently were processed by histology and for immunohistochemistry using specific antibodies. It showed the presence of cells c-kit/CD-117, with diverse degrees of positivity, distributed mainly in the interstitial peritubular area of the human testicle. The peritubular myoides cells were positive to the presence of the actin smooth muscle and androgen receptor. The neurofilaments elements (+) only were observed in the vascular tunic. The specific immunohistochemistry describe the presence of the interstitial cells of Cajal in human testicular interstitium, opening a new perspective for the functional interpretation of the testicular cellularity and tubular motility. Possibly associated functionally to peribubulars cells of smooth muscle to regulate the mobility of the seminiferous tabules, whose integration and function would be androgen dependent. The cells that express the c-kit receptor, were found exclusively in the interstitial compartment. This cellular type in addition of the muscular cells of peritubules and the absence of nervous fibers to the interior of the testicle, could be responsible for the regulation of tubular mobility, as it happens in the gastrointestinal apparatus.

El objetivo de este trabajo fue identificar la presencia de células interticiales de Cajal, células musculares lisas, células nerviosas y células que expresan receptores de andrógeno en el testículo de humano adulto, usando inmunohistoquímica específica para: c-kit/CD-117, músculo liso actina específico (ASMS), neurofilamentos (N) y para receptores de andrógenos (AR). Las muestras fueron obtenidas de pacientes (n=10) con diagnóstico de cáncer prostático sometidos a cirugía de orquiectomía. Las biopsias se procesaron para histología e inmunohistoquímica usando anticuerpos específicos. Se muestra la presencia de células c-kit/CD-117, con diversos grados de positividad y distribuidas en el compartimento interticial del testículo. Las células peritubulares mioides fueron positivas para la presencia de músculo liso actina específico y para receptor de andrógenos. La marcación de neurofilamentos positivos, sólo fueron observados en la túnica vascular. Conclusiones: La inmunohistoquímica específica describe la presencia de células interticiales de Cajal en los interticios testiculares humanos, abriendo una nueva visión en la interpretación funcional de la celularidad testicular y la motilidad tubular. Lo anterior asociado a la funcionalidad de las células peritubulares (músculo liso) regularían la motilidad de los túbulos seminíferos. Este proceso posiblemente es andrógeno dependiente. Las células que expresan receptores c-kit se encuentran exclusivamente en los compartimentos interticiales, estas células en conjunto con las células musculares peritubulares agregado a la ausencia de fibras nerviosas al interior del testículo, podrían ser los responsables de la regulación de la motilidad tubular, similar a como se informa para el tracto gastrointestinal.

Benign Schwannoma of the Liver: A Case Report

A primary benign schwannoma of the liver is extremely rare. Only nine cases have been reported in the medical literature worldwide and no case has been reported in Korea previously. A 36-yr-old woman was admitted to our hospital with vague epigastric pain. The ultrasound and computed tomography scan revealed a multiseptated cystic mass in the right lobe of the liver. The mass was resected; it was found to be a 5x4x2 cm mass filled with reddish yellow fluid. The histological examination confirmed the diagnosis of a benign schwannoma, proven by positive immunoreaction with the neurogenic marker S-100 protein and a negative response to CD34, CD117 and smooth muscle actin. This is the first report of a benign schwannoma of the liver parenchyma in a Korean patient.

Gastrointestinal stromal tumors: a demographic, morphologic and immunohistochemical study.

BACKGROUND AND AIM: There is limited published information on gastrointestinal stromal tumors (GIST) in the South Asian region. This study was conducted to describe the demographic characteristics, organ distribution and frequency of risk categories in cases of GIST referred to a tertiary hospital. METHODS: Data pertaining to 37 cases of gastrointestinal stromal tumors received at the histopathology section of the Aga Khan University Hospital between December 2004 and July 2005 were analyzed. Immunohistochemical stains including vimentin, CD34, CD117 (c-kit), ASMA, desmin and S-100 were performed. RESULTS: Of 37 tumors, 24 (64.9%) were from males. The mean age of the patients was 50.0 years (95% CI 45.3-54.6). Tumors were categorized as high risk (27 cases; 69.2%), intermediate risk (4 cases; 10.3%) and low risk (3 cases; 7.7%). The most common site of involvement was the stomach (29.7%), followed by small bowel (24.3%), mesentery (10.8%), pancreas (8.1%), rectum (2.7%) and retroperitoneum (2.7%). In 21.6% of cases, the site of origin was not specified. The mean age at diagnosis was 50.9 years (95% CI 45.5 - 56.3) in the high risk and 44.8 years (95% CI 28.6 - 60.9) in the intermediate risk category. CONCLUSIONS: Cases of GIST referred to us were more frequently from men, most commonly from stomach or small bowel, mostly in the high risk category, and presented a decade earlier than in other reported series.

Tumores gastrointestinales estromales (GIST): Experiencia del Servicio de Cirugía del Hospital Clínico de la Universidad de Chile entre 1999 y 2005 / Gastrointestinal stromal tumors: Review of 15 patients

Background: Gastrointestinal stromal tumors (GIST) are the most common mesenchymatous tumors of the digestive tract. The pathological diagnosis is based on microscopy and immunohistochemistiy. Aim: To review the experience of our surgical unit in patients with GIST Material and methods: Review of medical records of 15 patients (aged 66+13 years, 11 women), with a pathological diagnosis of GIST, treated between 1999 and 2005. Results: The main presenting symptoms were melena in 40 percent, hematemesis in 20 percent, abdominal pain in 60 percent and anemia in 13 percent. In only one patient, the tumor appeared as an incidentaloma. All patients underwent upper gastrointestinal endoscopy A CAT scan was done in 87 percent, a barium swallow in 60 percent and a digestive endosonography in 20 percent. Thirteen tumors were located in the stomach and two in the small bowel. Mean tumor diameter was 5.3+1.7 cm. Surgical management was a tumor resection in 40 percent, a partial gastrectomy in 27 percent, a total gastrectomy in 20 percent and an intestinal excision in the rest. Mean hospital stay was 6.9+4.2 days. No postoperative complications were recorded. Conclusions: The main clinical presentation of GIST in this retrospective series was an upper gastrointestinal bleeding. Surgical treatment was devoid of complication.

A Case of Malignant Gastrointestinal Stromal Tumor of Ileum with Liver Abscess / 대한소화기학회지

Gastrointestinal stromal tumor (GIST) is an uncommon mesenchymal tumor of the gastrointestinal tract and is generally located in the stomach and small intestine. They usually present with abdominal pain, gastrointestinal bleeding, and palpable mass. Some patients present with rare symptoms that are more common in malignant GIST. Malignant GIST combined with a liver abscess has not been reported yet in the literatures. We report a case of 67-year-old woman who suffered from liver abscess combined by malignant GIST with central necrosis and fistula in the ileum. She complained of fever, chills, and abdominal pain. Abdominal CT scan showed huge liver abscess and ileal mass with air pocket. Small bowel series showed contrast material filling into the ileal GIST mass. An operation was performed and the final diagnosis was malignant GIST of the ileum with invasion into the sigmoid colon and urinary bladder.

Malignant gastrointestinal stromal tumor of the ampulla of Vater presenting with obstructive jaundice.

Malignant gastrointestinal stromal tumor (GIST) consists a rare neoplasm, developing in small intestine and stomach. The presenting manifastations include weakness, weight loss, nausea, melena and anaemia. The present case refers to a 65 years old female patient with a GIST of the ampulla of Vater presenting with obstructive jaundice. Diagnosis was achieved pre-operatively by biopsies collected through diagnostic ERCP. The tumour was locally excised, with preservation of the ampulla. The histological analysis suggested low grade GIST positive for both CD 117 (c-kit) and CD34. Two years after the surgery the patient remains free of disease. Malignant GIST of the ampulla of the Vater is extremely rare as only few similar cases have been described in the literature. This is the first time a GIST being presented as obstructive jaundice ever reported. Despite the unavailability of EUS-FNA, the diagnosis was set preoperatively and the tumor was resected.

Tumor estromal gastrointestinal: estudo de oito casos / Gastrointestinal stromal tumor: a report of eight cases

OBJETIVO: O diagnóstico e tratamento dos tumores estromais gastrointestinais (TEGI) têm evoluído a partir de estudos recentes de genética e biologia molecular. Tais avanços têm refletido em melhor sobrevivência dos doentes. MÉTODOS: Foi realizado estudo retrospectivo no período de novembro/1998 a julho/2004, em instituição universitária e em clínica privada dos autores, que identificou portadores de TEGI a partir de positividade para c-kit (CD 117), ao exame imunoistoquímico. RESULTADOS: Dos oito pacientes estudados, seis eram do sexo feminino (75 por cento), a idade média foi de 53,2 anos. A presença de massa abdominal palpável foi a apresentação mais comum (62,5 por cento). O estômago foi o órgão mais acometido (62,5 por cento) seguido pelo intestino delgado (37,5 por cento). O tamanho médio do tumor foi de 10,6 cm. Em todos, foi possível a ressecção com margens livres. Em quatro doentes houve recidiva local ou à distância, todos esses foram tratados com mesilato de imatinib, com resposta parcial em três e completa em um deles. Sete pacientes (87,5 por cento) estão vivos em um período de seguimento médio de 33,4 meses. Não foi possível avaliar o comportamento biológico do tumor a partir das variáveis estudadas em virtude da pequena casuística. CONCLUSÕES: Com base nos dados obtidos de oito pacientes com TEGI do presente estudo, observamos: prevalência dos TEGI em doentes do sexo feminino o estômago como órgão preferencialmente acometido, ausência de correlação entre tamanho do tumor e número de mitoses à análise histológica e taxa de sobrevivência de 87,5 por cento com um seguimento médio de 33,4 meses.

Could imatinib replace surgery in esophageal gastrointestinal stromal tumor

Gastrointestinal stromal tumors GISTs are cellular spindle, or epithelioid tumors that occur in the stomach, intestine, and rarely in the esophagus. A 61-year-old man was complaining of resistant dry cough with dysphagia for one month duration. Upper gastrointestinal tract endoscopic examination showed a polypoid mass 30 cm from the incisors obstructing 50% of the lumen, where multiple biopsies were taken. Magnetic resonance imaging MRI showed a mass in the wall of the esophagus extending into the thoracic cavity. Histologically, the stained sections with the routine hematoxylin and eosin as well as the immunohistochemical stains for CD117, CD34, S100, vimentin, and smooth muscle actin confirmed the diagnosis of esophageal GIST. The patient was treated with imatinib, 400 mg/day. There was a dramatic reduction in the size of the tumor with successful improvement of his symptoms after 2 months of treatment, which was confirmed by repeated upper GIT endoscopy, and MRI