We report two cases of a primary lung tumour characterized by complex gland-like spaces lined by simple cuboidal to columnar epithelium surrounded by a hyalinized spindle-cell fibroblastic proliferation reminiscent of adenofibromas of the female genital tract. The lesions occurred in a 54-year-old woman and a 56-year-old man. The tumours presented clinically as 1-2 cm, solitary 'coin' lesions and were discovered incidentally on routine chest X-rays. Both lesions were treated by lobectomy. One patient is alive and well with no evidence of disease after 8 years; the other died of myocardial infarction 5 years following resection of his tumour without evidence of recurrence. We interpret these lesions as benign hamartomatous growths; their main importance lies in distinguishing them histologically from other types of pulmonary hamartomas, pulmonary blastomas, intrapulmonary solitary fibrous tumours, and metastases from soft tissue and visceral sarcomas.