Introduction: Ampullary carcinomas are uncommon malignant tumours of the digestive system, they usually are adenocarcinomas presenting histologically as three types: intestinal, pancreaticobiliary and mixed. β-catenin is a multifunctional protein involved in physiological homoeostasis and intracellular adhesion. Abnormal nuclear accumulation of β-catenin has been described in many malignancies such as colon, breast, liver and others. The relationships between the immunohistochemical expression of β-catenin and the subtype, the grade and the stage of ampullary carcinoma are studied. Material and methods: A cross-sectional retrospective study was done on 25 formalin-fixed paraffin-embedded blocks of ampullary carcinoma: Cases were collected from the archives of the pathology department in the Gastroenterology and hepatology teaching hospital, medical city/ Baghdad from January 2019 to March 2022. The data of the patients and the characteristics of the tumour were derived from the pathological reports; additional sections from the block were stained with β-catenin immunohistochemically. Results: 25 paraffin blocks from patients with ampullary carcinoma (12 males, 13 females) were included in the study. 64% of the cases are classified as pancreaticobiliary, 20% as mixed, 12% as intestinal and 4% as adenosquamous type. Eighty-four percent of the cases are moderately differentiated, and the remaining is poorly differentiated. Most cases show strong β-catenin membranous staining and 80% express 3+ staining of cytoplasmic β-catenin. Regarding nuclear β-catenin staining, 56% has negative staining. Conclusion: No significant association was found between the cytoplasmic and the nuclear expression of β-catenin and the tumour type, size and lymph node status. The grade of the tumour showed a significant correlation with the cytoplasmic expression; while, no correlation was noted with the nuclear expression. This study results do not support the use of beta-catenin as a diagnostic marker or prognostic marker in ampullary cancers.

Neuroendocrine tumor (NET) is the most common tumors of the appendix which is usually found incidentally. Synchronous neuroendocrine tumor of the appendix and colonic carcinoma has been reported in previous case reports. The actual incidence of these synchronous tumors need to be determined by reviewing these case reports and the need to include appendectomy as part of oncological colorectal operations.