Adenocarcinoma arising in sigmoid colon neovagina 53 years after construction

BACKGROUND: In view of the rarity of vaginal agenesis, malignancy arising in the neovagina is extremely rare. CASE PRESENTATION: Here, we report a 76-year-old female with an adenocarcinoma arising in the sigmoid colon neovagina which was constructed 53 years ago for congenital vaginal agenesis. Vaginal endoscopy to examine vaginal bleeding revealed a protruding lesion occupying three quarters of the lumen in the vicinity of anastomosis of the residual vagina and sigmoid colon. Transvaginal ultrasonography revealed the muscularis propria layer (hypoechoic fourth layer) to be interrupted. CT revealed no distant metastasis. Total pelvic exenteration was performed based on the diagnosis of neovaginal cancer at the anastomosis site. The 45-mm tumor showed well-differentiated adenocarcinoma with a mucinous adenocarcinoma component. Immunohistochemistry showed no p16-overexpressing tumor cells, suggesting the lack of human papilloma virus infection. CONCLUSIONS: Although rare, clinicians should be aware of cancer that arises in the ectopic intestine when anastomosed with other organs.