PMP is a rare condition, which, although of "borderline malignancy," is invariably fatal. Difficulties exist with the definition of PMP. It has been broadly applied to include a heterogenous group of pathologic lesions that present clinically with "jelly belly" due to mucinous ascites. The relatively few reports in the literature commonly use different pathologic definitions, and there is no consensus on the point of separation between PMP and carcinomatosis secondary to a mucinous adenocarcinoma. Sugarbaker has suggested "the term pseudomyxoma peritonei syndrome be strictly applied to a pathologically and prognostically homogenous group of cases characterized by histologically benign peritoneal tumors that are frequently associated with an appendiceal mucinous adenoma." This definition excludes all cases with mucinous adenocarcinoma. The optimal treatment is undoubtedly complete tumor excision, by complex surgical peritonectomy procedures, taking on average 10 hours. Surgery is usually combined with intraperitoneal, and now intraoperative heated chemotherapy. These techniques have a high morbidity and mortality. The rarity of the condition, together with the risks associated with definitive treatment, suggests that such treatment ought to be centralized in a few centers, covering a large population. The search continues for safer, less aggressive treatments, but is hampered by a lack of hard evidence and the absence of experimental animal or human models to evaluate emerging strategies.