Verruca Vulgaris Eruption Arising in the Setting of a Tyrosine Kinase Inhibitor

A 71-year-old female with breast cancer presented with a generalized papular rash that began following the initiation of rebastinib. Examination revealed scattered pink to skin-colored verrucous papules on the forehead, extremities, and back. A biopsy showed hyperkeratosis, hypergranulosis, digitated epidermal hyperplasia, and dilated blood vessels at the tips of dermal papillae consistent with verruca vulgaris. The patient discontinued rebastinib due to muscle weakness and the lesions resolved. Rebastinib is an antineoplastic agent that targets several tyrosine kinases. Tyrosine kinase inhibitors (TKI) frequently cause cutaneous adverse events, but to date, there have been no reported cases of a verruca vulgaris eruption arising in the setting of TKI treatment. Recent studies indicate that TKIs can have immunosuppressive effects by decreasing T-cell levels. We postulate that rebastinib induced an immunosuppressive state in our patient which permitted human papillomavirus (HPV) proliferation. To our knowledge, this is the first report describing a verruca vulgaris eruption with TKI therapy.