- AIMS: Breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) is an uncommon complication associated largely with textured implants. It is important that the symptoms associated with BIA-ALCL are recognised and that robust pathways are in place to establish the diagnosis. The aim of this paper is to review what is known of the incidence of the disease, current thoughts on pathogenesis, patterns of presentation and pathological features to provide standard guidelines for its diagnosis. METHODS AND RESULTS: Systematic review of the literature via PubMed covering cases series, modes of presentation, cytological, histological and immunohistochemical features and disease outcome. Since 1997, 518 cases throughout 25 countries have been registered on the American Society of Plastic Surgeons PROFILE registry, with an estimated risk for women with an implant of one to three per million per year. It most frequently presents as a late-onset accumulation of seroma fluid, sometimes as a mass lesion. The neoplastic cells are highly atypical, consistently strongly positive for CD30, with 43-90% also positive for EMA, and all are ALK-negative. Behaviour is best predicted using a staging system for solid tumours. CONCLUSION: BIA-ALCL is a rare but important complication of breast implants. While characterised by CD30-positive neoplastic cells this must be interpreted with care, and we provide pathological guidelines for the robust diagnosis of this lesion as well as the most appropriate staging system and management strategies. Finally, in order to generate more accurate data on incidence, we recommend mechanisms for the routine central reporting of all cases.