Immunotherapy in Young Adults with Mature Cystic Ovarian Teratoma-Derived Squamous Cell Carcinoma: A Case Series

Background Mature cystic teratomas (MCTs), also known as dermoid cysts, are common benign germ cell tumors. These predominantly benign tumors can become malignant, particularly in postmenopausal women; the overall transformation rate of MCTs is 1%-2%, accounting for approximately 80% squamous cell carcinoma of cases. Malignant transformation remains exceptionally rare in young adults. Case presentation: Herein, we report two cases of squamous cell carcinoma arising from MCTs in a 25-year-old patient, staged FIGO 2018 ⅢA1 and ⅠC2 according to the International Federation of Gynecology and Obstetrics (FIGO) 2018 classification. The results of histopathological examination confirmed squamous cell carcinoma arising from the teratomas. Immunohistochemical staining revealed programmed death-ligand 1 expression. Both patients underwent fertility-sparing surgeries and subsequently received adjuvant chemotherapy in combination with programmed death receptor 1 (PD-1) inhibitor immunotherapy. A complete clinical response was ultimately achieved. Patients 1 and 2 were monitored for 29 and 20 months after operation, respectively. A complete response was maintained in Patients1 and 2 for 14 and 16 months, respectively, as of the last follow-up. Conclusion Squamous cell carcinoma arising from MCTs is exceedingly rare in young adults and exhibits nonspecific clinical manifestations and imaging characteristics, hindering preoperative diagnosis. These tumors display highly aggressive biological behavior and are typically associated with a poor prognosis and a high postoperative recurrence rate. Immunotherapy intervention at diverse different time points for patients at different stages can increase their survival period.