Tumors of the ovaries in girls represent an actual problem in modern gynecology. First of all, this is due to diagnostic difficulties, due to the absence of characteristic complaints, asymptomatic course and the complexity of the gynecological examination, which leads to the establishment of an erroneous diagnosis, the lack of correct and timely treatment and, as a consequence, the occurrence of complications that often negatively affect the reproductive function of the patient in further. The differential diagnosis of ovarian tumors in girls is still one of the most important problems of modern practical gynecology. The presence of a combined pathology in many patients, which is in 30-40% according to the WHO, puts the problem of the possibility of the simultaneous correction by surgeon and gynecologist. In connection with the difficulty of diagnosing, the diagnosis of such patients must necessarily include an examination by a pediatric surgeon and gynecologist with ultrasound examination of the retroperitoneal space, abdominal cavity organs, and small pelvis. Errors in the differential diagnosis of genital and extragenital diseases occur quite often and are mainly due to the similarity of clinical symptoms. This article presents a clinical case of the diagnosis and management of a 14-year-old patient with an adjacent diagnosis, as well as diagnostic search criteria for the differential diagnosis of gynecological and surgical pathologies.