Abstract The risk of ovarian malignancy is rare in pregnancy with a reported incidence of approximately 1 in 50,000. Ovarian clear cell carcinoma (OCCC) accounts for 5% to 10% of all ovarian carcinomas with mean age of 50 to 55 years and is often associated with endometriosis. We present a case of 38-year-old G2P1 Asian female with an in vitro fertilization pregnancy and history of endometriosis who presented with the right adnexal mass. The transvaginal ultrasound performed during the early pregnancy was suggestive of endometrioma or desmoid tumor. At 32 weeks, the patient presented to the emergency department with preeclampsia and severe headache. An emergency cesarean section was performed due to worsening of the patient’s condition. An ovarian mass arising from the right ovary and with a friable and hemorrhagic internal surface was excised, which weighed 63 g and measured 14.0 × 10.5 × 3.0 cm. Its external surface was smooth, hemorrhagic, but without any excrescences. The serial sectioning revealed multiple cystic lesions filled with necrotic material overall occupying 80% of the mass. Microscopically, the viable ovarian tissue demonstrated tubulocystic/papillary architecture lined by hyperchromatic hobnail cells along with focal areas of solid sheets of tumor cells displaying clear cytoplasm. Immunohistochemical stains for Wilm’s tumor 1 and p53 were negative while positive for PAX8. These findings were indicative of OCCC without overexpression of wild-type p53. The PET scan performed few weeks after delivery showed widespread metastasis. We present a unique case of metastatic OCCC removed at the time of cesarean section in the late-preterm period. Our case not only emphasizes the need for definitive treatment option for endometriosis but also a close imaging surveillance of all masses diagnosed during pregnancy in women with risk factors such as endometriosis and Asian ethnicity. Furthermore, our study advocates the need for possible guidelines for management of such rare cases.