[A case of extramammary Paget's disease with urethral invasion treated by construction of continent urinary diversion based on the Monti principle using the sigmoid colon].

Extramammary Paget's disease occurring in the female vulva is occasionally associated with invasive disease to urethra and bladder mucosa. For such cases, ensuring adequate surgical margin is essential. Not only adequate removal of tumor, but also urinary diversion is important for patient's quality of life. A 77- year-old woman was treated with excision of vulvar tumor, urethra, vagina, rectum and anus. The determination of excision area was decided according to the result of mapping biopsy including urethra and bladder. Then she received reconstruction of vulva using the gracilis muscle skin flap. We applied a technique of channel formation for intermittent catheterization using the retubularized sigmoid colon based on the Monti principle. The tube was implanted submucosally into the bladder to prevent the reflux of urine. Fifteen days after operation, self-intermittent catheterization was started successfully. Surgical margins were negative in urethra, skin, vagina and rectum. There are no obvious recurrence or metastasis 1 year after surgery.