SILICONE BREAST IMPLANTS - PATHOLOGY

Questions as to the bioreactivity of silicone breast implants (SBIs) h ave recently been intensely scrutinized, most notably by the media and legal system. Pathologists must be aware of the controversy and treat each SBI and associated tissue as a potential lawsuit. Grossly, silic one is a clear, viscous substance that may be observed either within o r extruding from a silastic bag. By light microscopy, silicone is a no nstainable, nonpolarizable, refractile substance. Thicker sections, es pecially when viewed by non-Kohler illumination, phase-contrast, and d arkfield microscopy will enhance visualization. Ultrastructurally, sil icone is an electron-dense, amorphous substance often located within p hagocytic vacuoles or extracellularly within the stroma. Correlating e lectron probe microanalysis allows for reliable identification. In mos t cases, a fibrous capsule surrounds the SBI, with the interface linin g varying from a virtually acellular to a synovial-like lining compose d of phagocytic and secretory cells. Silicone can often be identified within the fibrous capsule and also in distant tissues biopsied for su spected autoimmune disorders, such as synovium, skin, and lymph nodes, often without ultrastructural evidence of cytologic effects. This stu dy has demonstrated that silicone accumulates at distant tissue sites due to preexisting inflammation acting as a stimulus. Thus, silicone i s not a primary inducer of inflammatory disease processes. These findi ngs are supported by various large epidemiologic studies.