Successful Treatment of ROS1-rearranged Lung Cancer Complicated by Hypertrophic Pulmonary Osteoarthropathy with Crizotinib Therapy.

Hypertrophic pulmonary osteoarthropathy (HPO) is a paraneoplastic syndrome characterized by digital clubbing, arthritis, and periostitis. Tumor removal usually leads to the resolution of these symptoms. We herein report the efficacy of crizotinib treatment for treating the symptoms of HPO associated with c-ros oncogene 1 receptor tyrosine kinase (ROS1)-rearranged lung cancer. A 71-year-old woman presented with a pulmonary tumor and arthritis. She was diagnosed with a ROS1-rearranged lung adenocarcinoma [stage IIIB (cT4N2M0) ] with HPO. Crizotinib dramatically reduced the tumor size and resolved the symptoms. After two months of crizotinib treatment, she underwent lobectomy, and a pathological evaluation revealed ypstage IIIA (ypT3a, ypN1). Crizotinib treatment was effective for reducing the tumor size and improving the symptoms of HPO.