A 71-year-old man presents for consultation, with the chief complaint of intermittent, painless anorectal bleeding associated with bowel movements. He was diagnosed 5 years ago with a pT3N1 midrectal cancer that was treated with neoadjuvant chemoradiation therapy followed by a low anterior resection. A flexible sigmoidoscopy demonstrates rectal telangiectasias, and friability of the rectal mucosa distal to the anastomosis. Which histologic findings would confirm the diagnosis in this patient if biopsy samples are taken?