DETERMINATION OF SILICON IN BREAST AND CAPSULAR TISSUE FROM PATIENTS WITH BREAST IMPLANTS PERFORMED BY INDUCTIVELY-COUPLED PLASMA EMISSION-SPECTROSCOPY - COMPARISON WITH TISSUE HISTOLOGY

A method for analysis of silicon in tissue was developed to determine silicon content in breast parenchymal and periprosthetic capsular tiss ues of patients with silicone or saline implants and to compare levels in tissues from normal (nanaugmented) breasts. It is of interest to d etermine whether increased silicon content in tissues can be associate d with morbidity in patients who have received silicone implants. This manuscript addresses the issues involved in analysis of breast tissue samples for silicon and compares silicon levels with tissue histologi c Endings and patient morbidity. One hundred sixty tissue samples were obtained for silicon analysis from 72 patients; during augmentation, capsulectomy with or without replacement mammoplasty, mastectomy; or b iopsy procedures and were frozen in acid-washed polystyrene tubes at 2 20 degrees C until analysis. Samples were thawed, sectioned to approxi mately 0.1 g (dry weight), and digested in nitric acid before analysis by inductively coupled plasma emission spectroscopy, monitoring emiss ion intensity at 251.6 nm. Tissue silicon levels (breast parenchymal a nd periprosthetic capsular tissue) in patients with silicone gel impla nts were muck higher (mean, 9,287 mu g/g, n=106) than in patients with saline implants (mean, 196 mu g/g, n=37) or nonaugmented breasts (mea n, 64 mu g/g,n=17). Histologic examination was performed on 54 tissue samples stained with hematoxylin-eosin. Tissue samples were rated as t o degree of inflammation and calcification, and amount of giant cells, foamy histiocytes, and vacuoles containing a colorless refractory mat erial. Vacuolization and foamy histiocyte ratings correlated significa ntly with tissue silicon concentration. No correlations were found bet ween tissue silicon concentration and inflammation, calcification, or giant cell rating. Implant age (number of years an implant was in plac e before sampling) correlated with capsular tissue silicon concentrati on in patients with intact implants but not in those with ruptured imp lants. No difference in tissue silicon concentration was found between patients with or without signs or symptoms of morbidity. Using 0.1 g of tissue, the method was linear to 1,000 mu g/g, and sensitivity was 3.7 mu g/g. Precision between runs (mean, 5.1 mu g/g; coefficient of v ariance, 13.7%; n=13) was calculated from multiple analyses of a bovin e liver standard (National Bureau of Standards, reference material 157 7a). Significant biologic variability (21.4% to 52.5%) was seen in tis sues with high silicon levels. Paraffin-embedded, formalin-fixed tissu es are not amenable to silicon analysis by this method, because of lea ching of silicone from the tissues during preparation. Thus only fresh frozen tissue samples were used.