Abducens nerve palsy due to clivus metastasis in a patient with breast carcinoma: A rare case

Introduction: Breast cancer, comprising 25 % of all diagnosed cancers, predominantly affects women globally. While bone metastasis is common, occurrences at the clivus or skull base are rarely documented. Treatment varies from surgery in early stages to a multifaceted approach for advanced cases, incorporating chemotherapy, radiotherapy, and surgery based on staging and histology. Clinical presentation: A 40 -year -old female presented with a rapidly enlarging lump in her left breast and diplopia on right gaze. Histology was positive for invasive breast cancer (no special type) and Contrast -Enhanced Computed Tomography demonstrated metastatic deposits in multiple vertebrae and bilateral ilium. Further, magnetic resonance imaging of the brain and orbits revealed metastatic deposits in the clivus which extended upto medial wall of the cavernous sinus, causing compression of the right abducens nerve. Multidisciplinary Tumor Board review recommended chemoradiotherapy. Discussion: Metastases from breast cancer can occur locally or to distant sites like lymph nodes, bones, lungs, liver, and brain. Unusual symptoms, such as new -onset diplopia, trigger further investigation. Although bone metastases occur in 50-65 % of cases, clivus metastasis is rare. Treatment aims at extending survival, symptom management, and enhancing quality of life through chemotherapy and radiotherapy. Outcomes hinge on metastatic burden and regional therapy responsiveness. Distant metastases substantially reduce the 5 -year survival rate from 80 % to approximately 25 %, but cases often improve with regional interventions. Conclusion: Although an extremely rare occurrence, clivus metastasis might be considered in patients with a history of malignancy, in particular, breast malignancy, presenting with new -onset sixth nerve palsy.