A proposal of a new periimplant breast pathology classification into 3 types

Despite preventive measures, silicone breast implants can develop severe pathologies that necessitate surgical revision. At present, there is no standardized classification for the capsular tissue excised during such revisions, yet establishing one would be critical for elucidating the underlying causes and pathogenesis of implant failure. A histopathological typing scheme for capsular tissue in breast implant-related pathologies (PBI classification) was developed and its sensitivity compared with the clinical diagnosis. A newly adapted, substantially time-reduced Oil Red O staining protocol is to be applied to assess whether direct detection of silicone is sufficiently feasible. Three types were defined: fibrosis type 1 is characterized by a fibrous reaction with variable fibroblast cellularity. Silicone type 2 is defined by the presence of silicone deposits within and outside the capsular tissue. Malignancy type 3 is characterized by the presence of malignancies. A total of 150 cases from five different clinics (period: 2001–2018) were characterized as follows: fibrosis type 1, n = 104 (69.3%); silicone type 2, n = 42 (28.0%); malignancy type 3, n = 4 (2.7%). The sensitivity of clinical diagnosis for breast implant-related pathologies was 80.8%, 95% CI [71.9%, 87.4%] for fibrosis type 1; 54.8%, 95% CI [38.7%, 70.2%] for silicone type 2; and 0%, 95% CI [0%, 17.7%] for malignancy type 3. This classification makes a significant contribution to elucidating their etiology. The results for the interobserver (κ = 0.87) and intraobserver (κ = 1.0) reliability showed a high agreement, which adds to the robustness and reproducibility of this classification. Comparison of histopathological and clinical diagnoses revealed a marked discrepancy in the correct identification of silicone type 2. The newly adapted time shortened and readily applicable Oil Red O staining enables direct detection of silicone and is proposed, in addition to this classification, as a specific method for silicone detection in routine diagnostics.