Ovarian dysgerminoma is a potentially malignant tumor that develops from primary germ cells. In the structure of the incidence of malignant neoplasms of the ovary, dysgerminomas make up about 1-2%. Being a relatively common disease in childhood and adolescence, the tumor rarely occurs in gynecological practice in adults. In this case, ovarian dysgerminoma is sometimes manifested by an increase in the level of human chorionic gonadotropin in the blood serum and paraneoplastic hypercalcemia associated with the production of vitamin D. The tumor may be complicated by secondary infection. Such unusual manifestations of the disease naturally lead to diagnostic errors. The article presents a description of a rare clinical case of ovarian abscess in ovarian dysgerminoma, which at first misled the attending physicians with some discrepancy between the symptoms and laboratory data.