Synovial metaplasia in capsules of macrotextured and smooth breast implants: A comparative study.

BACKGROUND

Synovial metaplasia in periprosthetic breast implant capsules is a clinically relevant but understudied phenomenon, especially at the cellular level.

OBJECTIVES

The purpose of this study was to assess the prevalence, severity, histological features, and marker expression characteristics of synovial metaplasia in capsules surrounding Allergan Biocell macrotextured breast implants. Capsules surrounding Motiva SmoothSilk smooth implants were used for comparison.

METHODS

During secondary breast surgery, we collected 151 and 10 capsules of macrotextured and smooth implants, respectively (1 per patient). Specimens underwent histopathological and immunohistochemical assessment.

RESULTS

Histopathological features of synovial metaplasia were observed only in capsules surrounding Allergan Biocell macrotextured implants: 1, 20, and 130 cases of mild, moderate, and severe metaplasia, respectively. Depending on metaplasia severity, capsules exhibited distinct differences in synovial lining formation and inflammatory cell infiltration. No metaplasia was detected for Motiva SmoothSilk capsules. For marker expression, advanced stages of metaplasia showed significantly higher CD55 and CD68 expression (p<0.001 adjusted). α-SMA was higher in metaplasia versus no metaplasia (p<0.001) but did not increase in severe cases. PDGFRβ expression was higher in moderate cases versus the no metaplasia and severe groups (p<0.01). No differences were observed for CDH11 and vimentin. Our findings suggest a complex tissue response to macrotextured implants.

CONCLUSIONS

Synovial metaplasia was found only in capsules surrounding Allergan Biocell macrotextured implants (100%). Higher CD55 and CD68 expression was associated with more severe cases, while α-SMA and PDGFRβ expression changed nonlinearly.