A 78-year-old smoker patient with COPD (GOLD 3E) is admitted for COPD exacerbation. The initial examination shows abnormal fingers and nails. The hyponychial angle is 195 degrees and there is a positive Schamroth sign. A diagnosis of nail clubbing is made. Because the association of nail clubbing and COPD is rare, the history is completed and reveals significant weight loss over the past few months. A -pulmonary CT-scan shows a peri-hilar mass, and biopsy confirms small cell lung cancer.