The authors investigated tissue reaction around implanted silicone expanders, focusing on clinical morphological and morphometrical aspects. For use in breast reconstruction in post mastectomy patients, the surface of a medical-grade silicone elastomer was modified, without changing its bulk properties, by the addition of a pyrolytic carbon film. The presence of lipophagy, the number of foreign-body giant cells of histiocytic origin, and the number of MIB-1 positive nuclei (an index of proliferation for the reactive stromal population) were all seen to be influenced by the pyrolytic carbon coating. Indeed, all these parameters were lower in the membrane formed around Carbofilm TM-coated expanders, thus demonstrating the effective protective properties of pyrolytic carbon coating.