A case of mucinous cystic neoplasm of the liver: a case report.

A 71-year-old woman was referred to our institution for further investigation of epigastric pain. The patient had been detected to have a multilocular cyst in the medial segment of the liver measuring 69 mm in diameter at another hospital 2 years ago, and the diameter of the cyst had increased to 90 mm. Although the cyst had gradually increased in size, there was no evidence of mural nodules. As we were concerned about the malignant potential of the lesion, a left hepatic segmentectomy was performed. Pathologically, the cyst was lined by columnar and cuboidal epithelium with low-grade atypia. The epithelium covered an ovarian-like stroma, and the diagnosis was mucinous cystic neoplasm of the liver (MCN-L) with low-grade intraepithelial neoplasia. MCN-L is a rare disease and its characteristics are still poorly understood. MCN-L occurs at a lower frequency as compared to the counterpart of MCN of the pancreas, further investigations are necessary to clarify the biological malignancy of MCN-L.