Sorafenib-Induced Spiny Follicular Hyperkeratosis: A Case Report with Review of Literature

Sorafenib is a multikinase inhibitor used in the treatment of various solid tumors. Mucocutaneous adverse events are experienced by 70 to 90% of the patients receiving sorafenib, underscoring the importance of awareness among oncologists and dermatologists. Spiny follicular hyperkeratosis (SFH) is a benign and rarely reported skin reaction linked to sorafenib. It is characterized by flesh-colored or white, follicular hyperkeratotic spicules, preferentially involving the face, scalp, upper trunk, and upper arms. Besides being acknowledged as a paraneoplastic cutaneous manifestation of multiple myeloma, SFH has also been linked to a few diseases and drugs, other than sorafenib. However, the precise etiopathogenesis remains to be elucidated. We report an interesting case of SFH in a 14-year-old child, 1 week following the initiation of sorafenib. Trichodysplasia spinulosa, multiple minute digitate hyperkeratosis, keratosis pilaris, filiform warts, and pityriasis rubra pilaris are morphologically similar conditions that were excluded by clinicopathological correlation. A complete resolution of skin rash following sorafenib dose reduction further reinforced our diagnosis. Our patient also developed hand-foot skin reaction, facial erythema, and eruptive nevi during treatment. The regrowth of curly hair following chemotherapy-induced anagen effluvium was an interesting development in our case. We report this case to familiarize clinicians with this rare entity.