We describe the pathological findings in a case of tracheopathia osteoplastica (TPO) of minimal extent. Although described clinically such minimal lesions have not been previously studied pathologically. Our observations lend strong support to the view-point that the nodules of TPO develop as ecchondroses of the tracheal cartilage rings. It is anticipated that TPO of minimal extent will be increasingly identified clinically and diagnosed on biopsy specimens.