Immature Teratoma With Metastatic Gliosis

Immature teratomas are rare malignant tumors of the ovary. They are made of immature components of germ cell origin. The incidence of immature teratomas is highest in young adults aged 18 to 39. The prognosis heavily depends on the International Federation of Gynecology and Obstetrics (FIGO) staging system and is influenced by factors such as cell type, tumor grade, capsular rupture, and metastatic risk factors. Initial treatment is complete surgical resection. When indicated, platinum-based adjuvant chemotherapy with bleomycin, etoposide, and cisplatin (BEP) is the treatment of choice. Next-generation sequencing of the tumor can influence treatment in the recurrent setting. Temozolomide is an alkylating agent used to target high-grade gliomas. Bevacizumab is a targeted therapy that interferes with the process of angiogenesis by inhibiting vascular endothelial growth factor (VEGF). We report a 36-year-old female who presented with a 17.6cm x 10.5cm x 24.2cm intraabdominal mass and ascites. Upon tumor resection, she was found to have a stage IIIa, grade 2 immature teratoma of the left ovary, with glial tissue being the metastatic cell type. Disease progression continued despite treatment with BEP. She was then treated experimentally with six months of bevacizumab and temozolomide, given its rarity and targeted therapy for glial tissue. Despite monoclonal antibody therapy, the tumor progressed again and was treated with docetaxel and gemcitabine. A repeat CT of the chest, abdomen, and pelvis demonstrated scattered peritoneal implants that were increasing in size. Chromosome analysis was performed and revealed somatic mutations of MLH1, MSH2, MSH6, and PD-L1. The patient has requested a break from chemotherapy but will be treated with direct immunotherapy when she restarts. This case’s importance lies in its rarity because fewer than 10 cases of immature teratomas with metastatic glial tissue are noted in the world’s literature. Furthermore, this is the first reported case of this cell type being treated with immunotherapy in the world literature.