Aim of the study: Acute appendicitis is one of the most common causes of emergency surgical intervention. Most commonly it concerns children and young adults. Beside the inflammatory process there may also be neoplastic lesions in the appendix.

The purpose of this work was to describe two cases of patients treated in our facilities in the emergency duty department due to acute appendicitis in the course of mucin-secreting carcinoma of this organ.

Case description: We present the case of a 41-year-old woman and a 70-year-old man operated on due to acute appendicitis, in whom mucin-secreting carcinoma was histologically diagnosed. The patients underwent a planned right hemicolectomy with removal of the major omentum. After receiving the final histopathological examination results the patients were referred to a regional oncological facility with recommendations of further treatment

Conclusions:

1. Acute appendicitis may co-exist with other diseases of this organ.

2. Adenocarcinoma of the appendix is a rare neoplasm of epithelial origin in the gastrointestinal tract.