Abemacilib-Related Radiation Recall Dermatitis Post Breast Reconstruction: A Case Report and Literature Review.

Radiation recall dermatitis (RRD) is an inflammatory skin reaction confined to areas previously exposed to radiation, triggered by subsequent systemic therapy. This case report describes a female patient with hormone receptor-positive, human epidermal growth factor receptor 2-negative breast cancer. She received 6 cycles of neoadjuvant chemotherapy, followed by mastectomy with immediate tissue expander implantation and axillary lymph node dissection. Adjuvant radiotherapy and intensive endocrine therapy (endocrine therapy and abemaciclib) were administered postoperatively. After radiotherapy, the patient developed small, coin-sized skin flap necrosis. Two months after completing radiotherapy, she initiated abemaciclib treatment, which was followed by rapid progression of flap necrosis and increased exposure of the tissue expander. This flap necrosis was suggestive of RRD. This report details the clinical course, management strategies, and a review of relevant literature, aiming to provide valuable insights for clinicians in handling similar cases and enhance awareness of potential risks associated with this treatment combination.