[Pulmonary hypertrophic osteoarthropathy and clubbing of fingers in patients with lung cancer].

We examined clinical characteristics of patients with primary lung cancer associated with clubbing of the fingers or pulmonary hypertrophic osteoarthropathy. Clubbing was observed in 12.5% of patients with lung cancer. Squamous cell carcinoma was frequently associated with clubbing. Clubbing was found in all clinical stages. PaO2 and PaCO2 were normal in patients with lung cancer, which suggests that neither hypoxemia nor hypercapnia caused the clubbing in these patients. Pulmonary hypertrophic osteoarthropathy was found in three patients with lung cancer (two men and one woman, mean age 49 years). The incidence was 2.9% among lung cancer patients with clubbing, 0.22% in all lung cancer patients, and was apparently lower than those in reports from outside Japan. One of these patients has stage IIIA squamous cell carcinoma, one had stage IV large cell carcinoma, and one had stage IV adenocarcinoma. In all cases bone scans were useful for diagnosis and for following the clinical course.