Panitumumab-Induced Eruptive Seborrhoeic Keratosis in a Patient with Metastatic Colorectal Cancer

OBJECTIVES: Agents targeting the epidermal growth factor receptor (EGFR)-mediated signalling pathway are increasingly being used for the treatment of advanced lung, pancreatic, colorectal and head and neck cancers. CASE PRESENTATION: Here, we report the first case of eruptive seborrhoeic keratosis following panitumumab treatment, an anti-EGFR monoclonal antibody, in a 73-year-old patient with stage 4 (IV) colorectal cancer with hepatic metastasis. CONCLUSION: While panitumumab is an emerging therapy for RAS wild-type metastatic colorectal cancer, physicians should consider panitumumab as a potential cause of eruptive seborrhoeic keratosis. LEARNING POINTS: Panitumumab is a fully human monoclonal antibody targeting the epidermal growth factor receptor (EGFR), indicated for the treatment of wild-type RAS metastatic colorectal cancer. Dermatologic toxicity of all grades occurs in more than 90% of patients treated with EGFR inhibitors. To the best of our knowledge, we have reported here a rare side effect; panitumumab-induced eruptive seborrhoeic keratosis.