Sorafenib-induced hand-foot skin reaction: a Koebner phenomenon?

Sorafenib is a tyrosine kinase inhibitor prescribed primarily for the management of metastatic kidney cancer. It exhibits a good safety profile, but is the cause of a number of dermatological adverse effects. The most common and often the most troublesome is a specific hand-foot skin reaction (HFSR) affecting at least 30% of patients. It occurs predominantly on hyperkeratotic areas of the hands and feet that are subject to chronic pressure, suggesting the role played by repeated subclinical traumas in its pathophysiological mechanism. We report here two new cases of sorafenib-induced HFSR, but associated with identical lesions occurring on specific areas of friction (scar, elbows) and suggestive of a Koebner phenomenon. This provides information about the origin of the palmar and plantar lesions observed with sorafenib.