A 52-year-old man presented with diarrhea and abdominal pain. He was found to have a large (12 cm) ulcerative rectosigmoid mass and died of the tumor less than two months after symptoms were developed. At autopsy, the tumor had metastasized to the liver and lymph nodes (pericolic, small bowel mesenteric, and paraaortic). The photomicrographs show H&E stain and INI–1 immunochemistry.
Hee Eun Lee, M.D., Ph.D.
Resident, Anatomic and Clinical Pathology
Thomas Smyrk, M.D.
Consultant, Division of Anatomic Pathology
Professor of Laboratory Medicine and Pathology,
Mayo Clinic College of Medicine