Mature cystic
teratomas (MCTs), also known as
dermoid cysts, are the most common ovarian
germ cell tumors and the most common
ovarian neoplasms in patients younger than 20 years. MCTs mainly appear as pelvic masses that are made up of different types of well differentiated derivates of at least two germinative cell types. MCT of the ovary is always benign lesions with slow growth and good prognosis. Unfortunately, in about 1-2% of cases, it may undergo malignant transformation. At present, surgical treatment is the preferred option for the early stage of malignant transformation of
teratomas, while with a high postoperative recurrence rate. For advanced or recurrent malignant ovarian
teratomas, the effect of conventional
chemotherapy or
radiotherapy is poor, leading to high mortality. Thus, identifying novel treatment for malignant transformed MCTs is an urgently need in clinic. Recently, PD-1 antibody-based
immunotherapy has achieved great success in treatment of
lung cancer,
melanoma, and other malignant
tumors. However, its effect on the malignant transformation of ovarian
teratomas has not yet been reported. Here we reported a patient who suffered malignant transformation of
ovarian teratoma and responded well to
camrelizumab, an anti-PD-1 inhibitor.