NEOPLASMS OF THE APPENDIX AND PSEUDOMYXOMA PERITON

NEOPLASMS OF THE APPENDIX AND PSEUDOMYXOMA PERITONEI

Tumours of the appendix may occur in up to 0.97 per 100 /uni00A0 000 of the population. NETs account for approximately 30% of appendix neoplasms while epithelial tumours account for most other cases. Epithelial tumours may show mucinous or non-mucinous features and range in the aggressiveness of their behaviour from low grade to high-grade invasive with signet ring features ( Table 76.3 ). A small percentage of appendix neoplasms fall into a third category known as mesenchymal tumours and include lymphoma, neuroma, GIST , Kaposi’s sarcoma and granular cell tumour of the appendix. Most patients with appendix neoplasms are asymptomatic at diagnosis and the appendix tumour is commonly an inci dental finding at appendicectomy . Perforation of a mucinous appendix tumour with dissemination of epithelial cells and mucin production leads to a condition known as pseudomyx oma peritonei (PMP) ( Figure 76.15 ).