Colon Cancer Metastatic to a Urachus Diagnosed by PET/CT

A 50-year-old man presented with a mass in the transverse colon diagnosed by colonoscopy. He underwent a left hemicolectomy and was diagnosed with a moderately differentiated adenocarcinoma penetrating into the pericolic adipose but no lymph node metastases. His course was uneventful with enrollment in a monoclonal antibody research treatment protocol. Eight years later, he presented with hematuria. A PET/CT demonstrated a hypermetabolic right external iliac lymph node and a hypermetabolic mass within a urachal remnant. The mass was excised and pathologically proven to represent a metastasis from the original primary tumor.