A 72-year-old woman visited our hospital to clarify the etiology of pain, swelling and ulceration of the right large vulva labium. Rectal cancer and pulmonary metastatic tumor were detected, and the rectal cancer was resected. Biopsy from the right vulva labium revealed that the vulvar tumor was a metastatic cancer originating from rectal cancer. Our patient underwent regional resection of the right vulva labium and the area lacking tissue was covered by a rhomboid transposition flap. Our patient experienced necrosis of the tip of the flap and the wound was healed by secondary intention.