Brain metastases as a manifestation of late relapse in high-grade serous ovarian cancer: Diagnostic and therapeutic challenges

Brain metastases from ovarian cancer are uncommon, with an estimated incidence of 1%-3%, and are usually associated with advanced-stage disease and prolonged survival. We report the case of a 55-year-old woman diagnosed with metastatic high-grade serous ovarian carcinoma presenting with diffuse peritoneal carcinomatosis, pulmonary and lymph node metastases, and an elevated CA-125 level. She received first-line treatment with paclitaxel–carboplatin plus bevacizumab, achieving a marked clinical, radiological, and biological response with normalization of CA-125 levels. Although interval cytoreductive surgery was proposed, the patient declined surgery and further systemic treatment. She was subsequently monitored with serial thoracoabdominal CT scans and CA-125 measurements, and the disease remained clinically, radiologically, and biologically stable for 19 months. The patient then presented with gait disturbance and a right-sided pyramidal syndrome. Contrast-enhanced brain CT revealed 2 large solid-cystic metastatic lesions with extensive vasogenic edema and marked mass effect. Brain MRI confirmed these lesions and identified 2 additional small metastatic lesions that were occult on CT, highlighting the superior sensitivity of MRI for detecting small brain metastases. The patient was treated with corticosteroids followed by whole-brain radiotherapy, resulting in significant neurological improvement. Five-month follow-up contrast-enhanced brain CT demonstrated complete resolution of the cerebellar metastasis and stability of the dominant temporoparietal lesion. This case highlights the diagnostic and therapeutic challenges of isolated brain progression despite stable extracranial disease and normal CA-125 levels, emphasizing the complementary role of MRI and the importance of prompt neuroimaging in ovarian cancer patients presenting with new neurological symptoms.