A 73-year-old male with stage IV lung adenocarcinoma presented with leg swelling and clubbing of the fingers on both hands upon physical examination, and bone scintigrams demonstrated marked accumulation of 99mTc-MDP in the long bones adjacent to the patellae. A diagnosis of hypertrophic pulmonary osteoarthropathy associated with primary lung cancer was made. Radiofrequency ablation (RFA) was utilized for cytoreduction, because the patient refused chemotherapy. One-month follow-up CT scans revealed low density of the ablated area associated with ablation necrosis. Cytoreduction by RFA rapidly alleviated the arthralgia and swelling, but not the clubbing of fingers. Follow-up bone scintigrams demonstrated a reduction in patellar uptake after RFA.