(OBQ08.56)
A 55-year-old man complaining of increasing problems with constipation undergoes a biopsy of a mass after a digital rectal exams reveals a fullness. The radiograph and micrograph of the biopsy specimen are shown in Figures A and B, respectively. Immunohistochemistry is positive for keratin and S-100. Following wide surgical resection, oncologic surveillance is necessary due to the high rate of which of the following?
QID:
442