Postoperative leucocytoclastic vasculitis in free flap mimicking venous insufficiency

SummaryA 29-year-old man, who had been diagnosed with myelodysplastic syndrome 1 year before, developed a wound on his thigh and knee due to necrotising fasciitis. Forty h after a free thoracodorsal artery perforator flap transfer, the colour of the flap changed from pink to purple, starting from the peripheral margin and epitheliolysis proceeded. Within a week, the colour returned to normal spontaneously and the flap survived completely. On punch biopsy, the lesion was confirmed as leucocytoclastic vasculitis, necrotising inflammatory disease of the small vessels in the dermis. This case demonstrates that leucocytoclastic vasculitis mimics postoperative venous insufficiency of a free flap; hence, differential diagnosis by careful judgement of vascular status is required. This rare occurrence needs to be considered in free-flap monitoring, especially in immunosuppressed patients.