Focally ulcerated gastric mucosal fragments showing a tubulovillous adenomatous lesion composed of elongated, branching tubular glands and villous projections lined by dysplastic columnar epithelium exhibiting nuclear enlargement, hyperchromasia, pseudostratification, nuclear crowding, and loss of surface maturation. Arising within and replacing the adenomatous component are areas of adenocarcinoma. The malignant component is predominantly composed of irregular, poorly formed glands, cords, and single infiltrating tumor cells with focal glandular differentiation. Tumor cells show marked nuclear pleomorphism, coarse chromatin, prominent nucleoli, a high nuclear-to-cytoplasmic ratio, and active mitosis. Focal necrosis is noted. A desmoplastic stromal reaction is present. The background gastric mucosa shows marked chronic active inflammation.
Large deep prepyloric ulcer with everted edge, about 4x3 cm.
Soft tissue fragments collectively measured 1.2 cm, totally embedded.
Stomach, endoscopic biopsy: