Ribociclib-Induced Erythema Dyschromicum Perstans (Ashy Dermatosis)-Like Pigmentation in a Metastatic Breast Cancer Patient

Ribociclib is a selective cyclin-dependent kinase (CDK) 4/6 inhibitor that has been approved in combination with endocrine therapy for the treatment of hormone receptor-positive/human epidermal growth factor 2-negative advanced or metastatic breast cancer. The main dermatological adverse events associated with CDK 4/6 inhibitors that are described in the literature include skin rash, an increased risk of alopecia, and stomatitis. Erythema dyschromicum perstans (EDP), also known as ashy dermatosis, is characterized by acquired small and large slate-gray hyperpigmented macules with erythematous borders. There are currently no published reports of EDP-like or pigmentary changes induced by CDK 4/6 inhibitors. This report describes the first case of EDP-like pigmentation associated with ribociclib therapy.