ABSTRACT
Low-grade appendiceal mucinous neoplasm (LAMN) are capable of transcoelomic dissemination following rupture of the appendix, leading to intraperitoneal spread of mucin and to the clinical syndrome known as pseudomyxoma peritonei (PMP). In selected patients with a perforated LAMN with little or no peritoneal disease, a policy of watch and wait may be recommended and definitive surgery may be deferred until peritoneal disease becomes apparent. Appendix tumours and PMP exhibit all the hallmarks of peritoneal malignancies, with an often protracted course; this makes them a paradigm for peritoneal disease. Perforation of the appendix tumour results in shedding of mucin and epithelial mucin-producing cells into the peritoneal cavity and distribution in a predictable fashion by the redistribution phenomenon. High-grade appendiceal mucinous neoplasms are a newly defined entity and include mucinous neoplasms similar to LAMN but with features of cellular atypia, including hyperchromatic cells, increased nuclear/cytoplasmic ratio and loss of cellular polarity.
