Background: Sorafenib has been approved for use in the treatment of metastatic renal cell carcinoma. Cutaneous side-effects are common, including rash, hand-foot syndrome, alopecia, pruritus, dry skin and erythema. We report an original unexpected cutaneous effect: multiple keratoacanthomas. In the light of a literature review of drug-induced keratoacanthomas, we discuss the potential underlying physiopathological mechanism.
Case report: Three weeks after starting treatment with sorafenib for metastatic renal cell carcinoma, a 64-year-old man developed skin lesions on the face, ears, forearms and thighs having the appearance of dome-shaped nodules with central keratotic cores. Eruptive keratoacanthomas were suspected and were in fact confirmed by histology. Thanks to effective antiangiogenic treatment and the mild discomfort of the keratoacanthomas, sorafenib could be continued. Three weeks after the end of treatment, all lesions had regressed and the patient's skin returned to normal.
Discussion: Although the precise aetiology is unknown, the development of eruptive keratoacanthomas is associated with impaired immunity, sun exposure, viral infection, genetic predisposition, radiation therapy and exposure to chemical carcinogens. A few cases of drug-induced keratoacanthomas have been described in the literature and certain immunosuppressant drugs have been implicated. This case suggests that the novel antineoplastic agent sorafenib has a complex activity that, in addition to tyrosine kinases inhibition, includes an immunosuppressant mechanism that can occasionally cause skin lesions.