Fig. 1

a MRI pelvis: 4 cm long thickening of the dorsal distal rectum wall without signs of sphincter infiltration; b 18F-FDG PET-CT: Metabolic active lesion at the anorectal transition without signs of lymphatic or distant metastasis
a MRI pelvis: 4 cm long thickening of the dorsal distal rectum wall without signs of sphincter infiltration; b 18F-FDG PET-CT: Metabolic active lesion at the anorectal transition without signs of lymphatic or distant metastasis