Localized palmar-plantar epidermal hyperplasia: a previously undefined dermatologic toxicity to sorafenib.

The development of multitargeted tyrosine kinase inhibitors has provided significant advances in the treatment of renal cell carcinoma. This case describes initial therapy for managing renal cell cancer with the administration of sorafenib, a multitargeted tyrosine kinase inhibitor. We report the development of localized palmar-plantar epidermal hyperplasia, a rare but significant cutaneous adverse event from sorafenib therapy. Mild-to-moderate dermatologic toxicity from sorafenib has been well described in the literature. We also review the current knowledge and the proposed hypothesis for the development of cutaneous events related to tyrosine kinase inhibitors. This particular case represents a unique form of dermatologic toxicity to sorafenib that has not previously been described in the literature.