BACKGROUND Anecdotal reports and one case-control study suggested an association, without evidence of causation, between breast implants and anaplastic lymphoma kinase-negative anaplastic large T-cell lymphoma (ALCL), a rare non-Hodgkin's lymphoma. This review summarizes the published evidence, including case reports and epidemiologic studies. METHODS A PubMed search limited to English language articles was conducted using the search terms "breast implant" and "lymphoma," "primary T-cell breast lymphoma," or "breast implant and ALCL" to identify all published cases of breast-associated ALCL. RESULTS A total of 18 publications were retrieved describing 27 cases of ALCL in breast implant recipients. Breast-associated ALCL occurred in women with and without implants. Approximately 78 percent of cases (21 of 27) were CD30 anaplastic lymphoma kinase-negative, with an indolent clinical course. Both saline- and silicone-filled devices were identified; however, implant style and surface texture were largely unreported. The tumor stage at diagnosis was I in 16 of 27, II or higher in seven of 27, or unreported in four of 27. No prospective epidemiologic study has linked implants and ALCL; however, a single case-control study in Dutch women reported increased odds of association between ALCL and implants, and an estimated frequency of one in 1 million women with and without breast implants. CONCLUSIONS An association, without evidence of causation, was reported between breast implants and ALCL. Further study is required to confirm this association. Breast-associated ALCL occurred rarely in women with and without breast implants and had a primarily indolent clinical course, which may provoke a revision of the World Health Organization nomenclature for lymphoma; however, aggressive clinical behavior was also reported. The cases of ALCL were not confined to a specific type of implant. CLINICAL QUESTION/LEVEL OF EVIDENCE Risk, V.