Bilateral Orbital Metastases in Breast Cancer: Literature Review Regarding a Rare Clinical Case

Bilateral orbital metastases from breast cancer are a rare condition, occasionally posing as the initial presentation of an undetected primary tumor. Hormone receptor-positive (HR+)/HER2-negative (HER2-) breast cancer, particularly the lobular subtype, is a common primary source. Despite advancements in breast cancer treatment, managing orbital metastases remains challenging due to limited data and their association with advanced multi-system end-stage disease. This study reports the first clinical case of bilateral orbital metastases as the initial presentation of bilateral breast cancer, successfully treated with a combination of a CDK4/6 inhibitor and an aromatase inhibitor. Additionally, it comprehensively reviews and analyzes clinical features, histological subtypes, treatment strategies, and outcomes associated with bilateral orbital metastases from breast cancer. The case involves a 53-year-old woman with elevated intraocular pressure and right optic disc edema in optical coherence tomography (OCT), leading to the discovery of synchronous bilateral orbital metastases and multicentric breast nodules. These were diagnosed as metastatic HR+/HER2- breast lobular cancer, and the patient showed a remarkable response to abemaciclib and letrozole. A review of 48 patients revealed a predominantly female population (96%) with a mean age of 59 years at diagnosis. A substantial proportion (37%) had no prior cancer history at presentation, and 65% had concomitant metastases in other anatomical sites, with 15% involving intracranial metastases. Common clinical findings included limited ocular motility (58%) and vision loss (33%). Imaging often showed infiltrating orbital soft tissues (71%), with 44% involving extraocular muscles. Histologically, most cases exhibited lobular characteristics (71%). Treatment modalities ranged from radiotherapy, chemotherapy, hormone therapy, and surgery, to immunotherapy. The overall mean survival in this cohort was 12 months (ranging from 0.5 to 41 months). In conclusion, bilateral orbital metastases from breast cancer are a clinically challenging condition. This study highlights their clinical features and treatment outcomes, underscoring the need for innovative therapeutic approaches to enhance their generally poor prognosis. The presented case, where bilateral orbital metastases from bilateral breast cancer responded well to a CDK4/6 inhibitor and an aromatase inhibitor, introduces a promising treatment avenue. Further research is warranted to optimize management and improve overall outcomes for these patients.