Minocycline-induced Hyperpigmentation of Transplanted Free Flaps: A Case Report

Minocycline has caused hyperpigmentation on various body parts, including the skin and mucosa, as a side effect. This is the first report of hyperpigmentation in transplanted free flaps. We present three head and neck reconstruction cases in two males and one female. The primary diseases were two cases of tongue cancer and one case of buccal mucosa cancer. Two anterolateral thigh flaps and one rectus abdominis musculocutaneous flap were transplanted after tumor resection with skin paddles placed intraorally. Minocycline was administered to prevent acneiform rash, which is a side effect of cetuximab during postoperative chemotherapy. The intraoral skin paddles turned blue 2 weeks to 1 month after administration. Minocycline causes hyperpigmentation by chelating the hemosiderin deposited in the skin due to capillary hemorrhage. Intraorally transplanted free flaps may be susceptible to minocycline-induced hyperpigmentation owing to vascular congestion, inflammation, and the intraoral environment.