The observation of stromal gastric tumor of 12 years old girl has been investigated. The diagnostics was carried out on tumor biopsy taken by a laparoscopy. An evident edema of stroma caused "pseudo-papillary" organization of epithelioid cell neoplasm prevented the right diagnosis established only by immunohistochemical staining of CD117 and CD34 markers. The absence of mutations in C-kit and PGFRA genes uncovered by molecular-genetic analysis is typical for stromal gastric tumors in child. The next gastric resection allowed to estimate tumor appearance and localization, histological organization, and to repeat immunohistochemical studying. This observation confirmed the correctness of diagnosis and established high level of Ki67 proliferative activity (12-15%) determined prescriptions of target medicamental therapy.