Transanal total mesorectal excision of giant villous tumor of the lower rectum with McKittrick–Wheelock syndrome: a case report of a novel surgical approach oleh Masahiko Fukase, Hiroshi Oshio, Sho Murai, Tomomi Kawana, Yusuke Saito, Emiko Kono, Yukiko Oshima, Gen Yunome, Shin Teshima, Masaaki Ito