Pseudomyxoma peritonei: Uninvited goblet cells, ectopic MUC2

Abstract

Pseudomyxoma peritonei (PMP) is a challenging clinical syndrome characterized by multifocal peritoneal collections of extracellular mucins. Mucins are high molecular weight, heavily glycosylated proteins differentially expressed by various types of epithelial cells. In this pathological condition, goblet cells originating from a mucinous tumor of the appendix gain access to the peritoneal cavity where they secrete mucin ectopically. Secreted mucin thus accumulates and forms the characteristic feature of the disease. Therefore, goblet cells and secreted mucins constitute the two key elements of the disease. MUC2 is the PMP's specific, predominant mucin. It is a highly viscous, gel-forming mucin that accounts for the characteristic appearance of PMP mucinous deposits as compared to the mucinous implants of ovarian origin. Mucin deposits are the real cause of PMP’s morbid complications irrespective of the site of origin, the mechanism of peritoneal spread, or the level of neoplastic transformation. In this article, role of mucin in gastrointestinal physiology and PMP pathology are reviewed and the potential of MUC2 as a therapeutic target are discussed