Mucinous cystic neoplasm of the liver with low grade dysplasia of the liver.

Mucinous cystic neoplasm (MCN) with low grade dysplasia of the liver is rare. It had been previously called hepatobiliary cystadenoma and is seen almost exclusively in women without an associated invasive carcinoma. There are different theories for development of MCN of the liver. One of these is developing from endodermal immature stroma or primary yolk cells implanted during embryogenesis. Another theory refers to the prevalence of hepatic mucinous cystic neoplasm in segment IV, which may support an implant origin because hamartomatous lesions commonly develop in segment IV. The third theory concerns the expression of oestrogen receptor or progesterone receptor in ovarian-like stroma, which also supports a putative role for female hormones in the tumorogenesis. MCN of the liver is a cystic-forming epithelial neoplasm, usually showing no communication with the bile ducts, composed of cuboidal to columnar, variably mucin-producing epithelium, associated with ovarian-type subepithelial stroma. We present a case of MCN with low grade dysplasia of the liver in a young woman whose working surgical diagnosis was Echinococcus cyst. The MCN diagnosis was confirmed with Immunohistochemical study.