Fig. 4

(a) A lower rectum rectal adenocarcinoma misdiagnosed as villous adenoma in a 48-year-old man. (b) The tumor showed abundant arborization vascular on color Doppler image; (c) the tumor presented regular hyper-enhanced on contrast-enhanced condition, and there were some minor necrosis areas in the tumor. (d) The biopsy needle (arrow) passes through the tumor center to acquire biopsy samples