[Swyer syndrome with gonadal non-dysgerminoma malignant germ cell tumors: a report of 15 cases in a national medical center].

Objective: To evaluate the incidence, treatment, and survival outcomes of Swyer syndrome with gonadal non-dysgerminoma malignant germ cell tumor (MGCT-NDG). Methods: A retrospective study was performed on Swyer syndrome patients with MGCT-NDG between January 2011 and December 2022 in Peking Union Medical College Hospital to investigate their characteristics and outcomes. Results: A total of 15 patients (4.9%, 15/307) with Swyer syndrome were identified in 307 MGCT-NDG patients. The average age at diagnosis of MGCT-NDG and Swyer syndrome were (16.8±6.7) and (16.7±6.6) years, respectively. Six cases were preoperatively diagnosed as Swyer syndrome, of which 4 cases received bilateral gonadectomy with or without hysterectomy, while the other 2 cases underwent removal of gonadal tumor and unilateral gonadectomy with hysterectomy, respectively. Of the 9 patients postoperatively diagnosed as Swyer syndrome, unilateral gonadectomy, removal of gonadal tumor, and unilateral gonadectomy with hysterectomy were performed in 6 patients, 2 patients, and 1 patient, respectively. Mixed malignant germ cell tumor (MGCT;10 cases), yolk sac tumor (4 cases), and immature teratoma (1 case) were the pathological subtypes, in the descending order. There were International Federation of Gynecology and Obstetrics (FIGO) stage Ⅰ in 6 cases, stage Ⅱ in 3 cases, stage Ⅲ in 5 cases, and stage Ⅳ in 1 case, respectively. Eleven patients received reoperation for residual gonadectomy after a average delay of (7.9±6.2) months, including 8 MGCT-NDG patients and 1 gonadoblastoma patient, no tumor involved was seen in the remaining gonads in the other 2 cases. Ten patients experienced at least one recurrence, with a median event free survival of 9 months (5, 30 months), of which 2 patients received surgery only at the time of initial treatment. All patients with recurrence received surgery and combined with postoperative chemotherapy. After a median follow-up of 25 months (15, 42 months), 10 patients were disease-free, 3 patients died of the tumor, 1 died of side effects of leukemia chemotherapy, and 1 survived with disease. Conclusion: The incidence rate of Swyer syndrome in patients with MGCT-NDG is about 4.9%; timely diagnosis and bilateral gonadectomy should be emphasized to reduce the risk of reoperation and second carcinogenesis in this population.