Multiple myeloma emerging after prolonged gefitinib treatment for non-small cell lung carcinoma

The coexistence of lung cancer and multiple myeloma (MM) is rare. A search of the English literature revealed only 5 case reports to date. We describe a case of MM that presented in a 78-year-old lung cancer patient after 20 months of treatment with gefitinib, an epidermal growth factor receptor tyrosine kinase inhibitor. We also review previously reported cases of concurrent development of lung cancer and MM.