Breast implant-associated ALK-negative anaplastic large cell lymphoma: a case report and discussion of possible pathogenesis.

Breast implant associated anaplastic large cell lymphoma (BIA-ALCL) is a recently recognized clinical entity, with only 39 well-documented cases reported worldwide, including 3 fatalities. Because of its rarity, the clinical and pathologic features of this malignancy have yet to be fully defined. Moreover, the pathogenesis of ALCL in association with textured silicone gel breast implants is poorly understood. Here we report a case of BIA-ALCL arising in a 67-year-old woman with a mastectomy due to breast cancer followed by implantation of textured silicone gel breast prosthesis. The patient presented with breast enlargement and tenderness 8 years following reconstructive surgery. MRI revealed a fluid collection surrounding the affected breast implant. Pathologic examination confirmed the presence of malignant ALCL T cells that were CD30+, CD8+, CD15+, HLA-DR+, CD25+ ALK- and p53. A diagnosis of indolent BIA-ALCL was made since tumor cells were not found outside of the capsule. Interestingly, an extensive mixed lymphocytic infiltrate and ectopic lymphoid tissue (lymphoid neogenesis) adjacent to the fibrous implant capsule were present. The patient was treated with capsulectomy and implantation of new breast prostheses. Six months later, the patient was found to have BIA-ALCL involvement of an axillary lymph node with cytogenetic evolution of the tumor. To our knowledge, this is the sixth reported case of aggressive BIA-ALCL. Unique features of this case include the association with lymphoid neogenesis and the in vivo cytogenetic progression of the tumor. This case provides insight into the potential role of chronic inflammation and genetic instability in the pathogenesis of BIA-ALCL.