Tubulovillous adenomatous polyp featuring a complex architectural mixture of elongated villous fronds and branching tubular glands. The epithelium exhibits high-grade dysplasia with pseudostratified, hyperchromatic nuclei and a complete loss of goblet cell polarity. Within this precursor lesion, focal intramucosal adenocarcinoma is identified, characterized by back-to-back, glandular proliferations infiltrating the lamina propria. Neoplastic cells exhibit marked nuclear pleomorphism, vesicular chromatin, and prominent nucleoli.
There is no evidence of submucosal invasion or a desmoplastic stromal response in the current material.
Sessile sigmoid polyp.
Soft tissue fragments collectively measured 1 cm, totally embedded.
Sigmoid colon, sessile polyp; excision: