[en] In summary, a case has been reported of an asymptomatic 27-year-old man in whom an expanding extrapleural lesion arising in the posterior segment of the right third rib was detected incidentally. The plain films showed the mass to be well circumscribed, with the degree of density of the mass considerably less than that usually noted in an extrapleural mass of this type. CT studies from -26 to +78, suggesting a lesion containing fat, and in view of the histological sections obtained after the lesion was resected, a lipoma containing scattered areas of residual bone trabeculae was diagnosed. (orig./SHA)