Brain metastasis of ovarian cancer >20 years after initial diagnosis: A case report

Brain metastasis from ovarian cancer, particularly from clear cell ovarian cancer, is extremely rare and its pathology remains unclear. In the present study we treated a patient in whom this cancer was diagnosed after chemotherapy was administered for lung metastases. The patient, a 76-year-old woman, presented to Department of Obstetrics and Gynecology, Showa General Hospital (Tokyo, Japan) in February 2025 with sudden confusion and dizziness. The patient was surgically treated for ovarian cancer 20 years previously that displayed two clear histological types: Left clear cell and mucinous carcinomas and right endometrioid carcinoma. The patient was treated several times for recurrent metastases in the umbilicus and inguinal lymph nodes, of either clear cell or endometrioid carcinoma. The treatment administered varied from resection to radiotherapy. In 2016, lung metastasis was suspected, but the lesion size remained unchanged for several years. In 2019, the left inguinal lymph node again became swollen, and re-irradiation was performed for 2 weeks. In 2023, the right lung metastases grew larger and palliative radiotherapy was administered at another hospital. The right lung metastases continued to grow, and the patient returned to our hospital in May 2024 with a severe cough; metastasis from ovarian cancer was diagnosed. Paclitaxel-carboplatin chemotherapy was resumed for 6 months; the tumor grew slightly smaller, and the severe cough disappeared. The patient underwent maintenance olaparib therapy from January 2025 for platinum-sensitive recurrent ovarian cancer. After presenting to our department in February 2025, imaging studies revealed multiple substantial brain metastases and growth of the lung metastases. Palliative whole brain radiotherapy was administered, with the confusion improving slightly. The patient was transferred to a nursing home. Multiple pathological types coexisted in our patient, creating a complicated condition that, after various treatments were administered, was difficult to comprehend. Appropriate pathological diagnosis through biopsy, as well as comprehensive consideration of the treatment strategy based on the characteristics of the pathological type, is necessary.