Picture Prognosis

A 64-year-old male with a history of varicose veins, hypertension, and hyperlipidemia presented with severe central upper abdominal pain, nausea, vomiting, and a history of constipation and left lower quadrant pain. CT and MRI revealed a 5.5 cm rectal mass with adjacent lymph nodes. An exploratory laparotomy revealed a 10 x 5 cm exophytic bilobed mass in the distal sigmoid. The final histopathology report is shown in the picture. Diagnosis?