NEOPLASTIC LESIONS OF THE APPENDIX

Neoplasms occur in 0 . 5 per cent of appendices. Ultrasonography or co mputed tomography is beneficial, but preoperative detection is rare. A t operation, the diagnosis is considered in under half of cases. Mucoc ele, localized pseudomyxoma peritonei, benign tumours and most appendi ceal carcinoids are cured by appendicectomy alone. Right hemicolectomy is indicated for: (1) invasive adenocarcinoma; (2) tumours close to t he caecum; (3) lesions larger than 2 cm; (4) mucin production; (5) inv asion of the lymphatics, serosa or mesoappendix; and (6) cellular pleo morphism with a high mitotic rate: Tumours of 1-2 cm, small mucinous c arcinoids, adenocarcinoma confined to the mucosa, and tumours in child ren may be treated by appendicectomy alone at the surgeon's discretion . The 5-year survival rate associated with classical carcinoid is more than 90 per cent. The prognosis of mucinous carcinoid is intermediate between that of classical carcinoid and well differentiated adenocarc inoma. The prognosis of adenocarcinoma is determined by Dukes' stage a nd is similar, stage for stage, to that of colorectal carcinoma.