Blue-grey hyperpigmentation in acne after vandetanib therapy and doxycycline use: A case report.

Vandetanib is an oral tyrosine kinase inhibitor with cutaneous adverse effects that include the development of acne. We present a patient who underwent vandetanib therapy for stage IV medullary thyroid cancer in conjunction with the use of doxycycline for acne that developed. After vandetanib use, blue-grey pigmentation developed in the acne on his face, chest, back, and arms, which darkened after the use of doxycycline. We review the literature to report that this blue-grey hyperpigmentation was likely vandetanib-induced but may have been the result of both drugs being used in combination.