Cholangiocarcinoma that infiltrated a Periampullary Duodenal Diverticula and the head of the pancreas (15 of 20)

Neoplastic tubulopapillar tissue infiltrating and replacing the Vater ampulla.

Histological Grade

Most cholangiocarcinomas (95%) are adenocarcinomas.
Adenocarcinomas are classified 1 to 4 according to the percentage of tumour that is composed of glandular tissue.
Some types of adenocarcinoma are however not graded: carcinoma in situ, clear cell adenocarcinoma, and papillary adenocarcinoma.
Signet ring cell carcinoma is given a grade of 3 and small cell.
Carcinoma a grade of 4. Squamous cell carcinomas are graded according to the least differentiated areas. Most studies have demonstrated a relation between histological grade and postoperative outcome although stage is more important.