Fig. 1

CT and PET/CT for pelvic imaging in anorectal malignant melanoma. A seventy-three-year-old female patient (patient 5) with a small iliacal lymph node metastasis on the right side (dashed arrow) and a relapse from anal melanoma. Contrast-enhanced CT reveals a small lymph node beside the right internal iliac artery of round configuration with uncertain dignity (a). PET/CT, however, indicates increased FDG uptake suspicious for metastasis (b). The follow up examination 9 months later provides clear evidence of progressive lymphatic metastasis on the right iliac side (arrow) on CT (c) and PET/CT (d) images. The lymph node is enlarged with a destroyed anatomical structure and increased glucose uptake. PET/CT enabled detection of lymph node metastasis in an early state