A pulmonary nodule was incidentally detected in a 50-year-old man during a routine health evaluation. High-resolution computed tomography (HRCT) showed that the lesion had the appearance of a collection of multiple tiny nodules. Histologic examination of the resected specimen revealed a single hamartoma resembling a bunch of grapes. Pulmonary alveoli and bronchioles were entrapped within the hamartoma with tumor buds appearing in a multicentric manner, thereby producing the unusual HRCT findings. Review of chest radiographs taken over the previous 20 years indicated that the tumor doubling time was 4968 days.