Aim: We present a rare case of gastrointestinal tumor in a boy. Introduction: Gastrointestinal stromal tumors (GISTs) represent rare mesenchymal tumors in pediatric population. Most of these tumors originate in the stomach and very rarely in the oesophagus. They are more frequent in young girls. As opposed to adult GISTs, those that occur in childhood show mutations in PDGFRA receptors or so called “Wild type” mutations. Case report: A fifteen years and 2 months old boy with symptoms of dysphagia and stenocardia for the last six months. Endoscopy showed nodular solid lesion at the distal part of the thoracal oesophagus, later surgically removed. Dimensions of the lession were 35x25x20mm with whitishPOSTER SESIJA 57 MATERIA MEDICA • Vol. 34 • Issue 1, suplement 1 • april 2018. yellow cut surface and areas of hemorrhage. Histology showed predominant spindle cell pattern with minor epithelioid component, with pronounced cellular and nuclear pleomorphism, rare areas of necrosis and hemorrhage, with the mitotic count more than 18 per 50 high power fields and numerous atypical mitotic figures. Immunohistochemical studies were CD117 and DOG-1 negative, but positive for PDGFRA. Tumor expressed focal alpha-SMA and CD34 positivity. Conclusion: Informations regarding pediatric gastrointestinal stromal tumors are still insufficient. Even though these tumors are rare in childhood, when analysing mesenchymal neoplasms potential GISTs should be considered.