Abemaciclib-Associated Skin, Hair, and Nail Toxicities: A Case Report

Abstract

Abemaciclib is a cyclin-dependent kinase 4/6 inhibitor that is utilized to manage hormone-sensitive human epidermal growth factor receptor-2 positive metastatic breast cancer. Palbociclib and ribociclib are types of other orally administered CDK4/6i that share similar safety and tolerability compared with Abemaciclib. Reported side effects include reversible neutropenia of a lower grade, gastrointestinal toxicity, and anemia. CDK4/6i could induce dermatological side effects. Although less frequent, cutaneous adverse effects of CDK4/6i account for 25% of medication discontinuation. Frequent cutaneous adverse events are rash and pruritus; nonetheless, hair loss, nail changes, vitiligo, and photosensitivity reactions, were also reported to a lesser extent. Herein, we report a case of hair, nail, and pigmentary disorder that occurred 10 months after initiating abemaciclib treatment.

Keywords: abemaciclib; cdk4/6i; cyclin-dependent kinase 4/6 inhibitors; palbociclib; ribociclib.

Figure 1. (A and B) Both middle fingernails displayed onycholysis; (C and D) All nails demonstrated roughness and longitudinal ridges (trachonychia)

Figure 2. Both big toenails are thick, rough, and hyperkeratotic with proximal separation in the right big toenail

Figure 3. (A) Scattered hyperpigmentation macules over the trunk; (B and C) There is hyperpigmentation in the palms and soles