Vortex keratopathy associated with ribociclib

Introduction Cyclin-dependent kinases 4 and 6 (CDK4/6) inhibitors are the new generation drugs that have been started to be used in our clinical practice recently. These drugs have been shown to have better progression-free survival compared to standard therapy in patients with hormone receptor-positive (HR) and human epidermal growth factor receptor 2 (HER-2)-negative breast cancer. The most common side effects of CDK 4-6 inhibitors are neutropenia, nausea, leukopenia, fatigue, and diarrhea. This case demonstrated vortex keratopathy in both eyes, a rare condition in patients with breast cancer treated with ribociclib. Case report A 68-year-old female patient was diagnosed with locally advanced HR (+)/HER2 (−) breast cancer in March 2015. In June 2021, bone metastases were detected. The patient was started on ribociclib and fulvestrant. After three cycles of ribociclib and fulvestrant treatment, she was admitted with the complaint of blurred vision in her left eye. Slit-lamp biomicroscopy examination revealed subepithelial haze with central subepithelial whorls in both corneas, more in the left eye, and also a mild punctate epithelial staining was observed with the application of fluorescein dye. Management and outcome Ribociclib treatment was immediately discontinued and no changes were observed in the cornea and vision levels during the one-month follow-up. Discussion Routine and regular follow-up eye examinations in breast cancer patients treated with ribociclib may benefit patients in our daily clinical practice and may help us to detect side effects at an early stage and to manage them more effectively.