Breast implant-associated anaplastic large cell lymphoma (BI-ALCL) is a very rare form of T-cell lymphoma that arises in association with various kinds of breast implants. In the recently revised WHO classification of hematological malignancies, BI-ALCL is introduced as a new provisional disease entity, distinct from the other types of ALCLs already recognized (Oishi 2018). While the morphological and immunophenotypical features of BI-ALCL are indistinguishable from those of systemic ALK-negative ALCL, the specificity of the newly described entity is its clinical presentation in association with and the vicinity of a breast implant.