Breast Implant Illness May Be Rooted in Mast Cell Activation: A Case-Controlled Retrospective Analysis

To investigate the possible association between breast implant illness (BII) and mast cell activation syndrome (MCAS), which often manifests increased mast cells (MCs) in assorted tissues and may explain BII symptoms. Mechanisms by which implants cause BII symptoms remain unclear, but BII and MCAS symptom profiles heavily overlap, warranting investigation of potential linkage. We retrospectively analyzed 20 implant patients who underwent explantation and total capsulectomy; 15 self-reported preoperatively they had BII (subject group); 5 felt they did not [control group 1 (CG1)]. Five prophylactic mastectomy patients constituted control group 2 (CG2). Subjects and CG1 patients completed BII symptom questionnaires preoperatively and multiple points postoperatively. With CD117 staining, average and maximum mast cell counts (MCCs) in resected tissues were determined. Mean BII symptom score 2 weeks postexplantation was reduced by 77% (P < 0.0001), and 85% by 9 months. Analysis suggested BII in CG1 patients, too, who improved similarly. Among CG2 patients, healthy breast tissue showed mean and maximum MCCs of 5.0/hpf and 6.9/hpf. Mean and maximum MCCs in capsules in BII patients were 11.7/hpf and 16.3/hpf, and 7.6/hpf and 13.3/hpf in CG1 patients. All intergroup comparisons were significantly different (P < 0.0001). MCCs in peri-implant capsules in BII patients are increased; some implanted patients appear to have unrecognized BII. Given that neoantigenic/xenobiotic exposures commonly trigger dysfunctional MCs in MCAS to heighten aberrant mediator expression driving inflammatory and other issues, further investigation of whether BII represents an implant-driven escalation of preexisting MCAS and whether an MCAS diagnosis flags risk for BII seems warranted.