Breast Implant Illness and Autoimmune/Inflammatory Syndrome Induced by Adjuvants: Mechanistic Rationale and a...

Breast implant illness (BII) describes a constellation of systemic symptoms reported by some patients after breast implantation, including fatigue, cognitive dysfunction, arthralgia, myalgia, sicca symptoms, skin manifestations, and mood disturbance. Autoimmune/inflammatory syndrome induced by adjuvants (ASIA) provides a broader conceptual framework in which silicone and other biomaterials may contribute to immune dysregulation in susceptible individuals, although causality remains controversial and no validated diagnostic biomarker exists. This narrative review summarizes current evidence on BII and implant-related ASIA, focusing on epidemiology, clinical presentation, biological plausibility, diagnostic evaluation, explantation outcomes, and implant-associated complications. Proposed mechanisms include chronic foreign-body inflammation, silicone gel bleed and particulate migration, macrophage activation, inflammasome signaling, cytokine dysregulation, bacterial biofilms and biofilm-derived metabolites, adaptive immune activation, autoantibody formation, and host genetic susceptibility. The review also distinguishes BII/ASIA-like presentations from breast implant-associated anaplastic large cell lymphoma and other rare implant-associated malignancies. A practical multidisciplinary diagnostic and management algorithm is proposed to support structured assessment, red-flag triage, exclusion of alternative diagnoses, patient-centered counseling, and individualized decision-making regarding medical management and explantation.