Chronic myelomonocytic leukemia blast crisis in a patient with advanced non-small cell lung cancer treated with EGFR tyrosine kinase inhibitors.

A 59-year-old woman with epidermal growth factor receptor gene (EGFR) mutation-positive advanced lung adenocarcinoma was treated with afatinib after a diagnosis of chronic myelomonocytic leukemia (CMML). Twenty-one weeks later, she developed agranulocytosis, and CMML subsequently progressed to blast crisis. After complete remission of CMML, gefitinib was initiated; however, agranulocytosis recurred. This is the first reported case of both EGFR mutation-positive advanced non-small cell lung cancer with CMML, and of CMML blast crisis. Physicians should be aware of such risks and monitor EGFR-TKI-treated patients with myeloid neoplasms accordingly.