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hepatic cystic biliary lesions

Tuesday 3 May 2011

Types

- von Meyenburg complex

  • A von Meyenburg complex can be incidentally found either as single or multiple subcapsular nodules of small size, usually less than 5 mm in diameter.
  • This complex may represent part of the spectrum of ductal plate malformation and may be related to adult type polycystic disease.
  • Histologically, von Meyenburg complex is located within or adjacently to portal tracts and it is composed of multiple-branched bile ducts, sometimes with an angulated appearance, set in a collagenous stroma. These tubular structures contain bile and/or eosinophilic material.

- biliary adenofibroma (BAF)

  • generally presents as a large-sized nodule with a solid microcystic appearance.
    - bile duct adenoma
  • Bile duct adenoma is generally a well-demarcated, small-sized lesion with a diameter ≤1 cm, usually located directly underneath the liver capsule. Occasionally, this lesion may present as two or more nodules with a maximal diameter of 2 cm. Histologically, it is characterized by closely packed tubules with narrow lumens, lined by cuboidal bile-type epithelium, set in an edematous to dense fibrous stroma which may contain a variable amount of inflammatory cells. Unlike BAF, these tubules show more irregular outlines and less cystic configuration while stromal component is less prominent. Bile duct adenoma is not a true neoplasm but it is currently regarded as a peribiliary gland hamartoma or a localized reactive ductular proliferation as result of a previous unknown injury.

- biliary cystadenoma

  • Unlike BAF, biliary (peribiliary) cystadenoma is a large-sized cystic tumour with multilocular appearance, in which cysts may be up to 15 cm of diameter. Two histological variants were recognized: serous and mucinous types. The former consists of small cysts lined by a single layer of low cuboidal or flat epithelium with a clear cytoplasm; the latter contains cysts lined by columnar, cuboidal or flattened mucous-secreting epithelial cells with occasionally papillary projections and an ovarian-like stroma appearance, especially if the lesion occurs in women, with a characteristic immunoreactivity for oestrogen and progesterone receptors.
    - congenital biliary cysts (simple biliary cysts)
  • The congenital biliary cysts (simple cysts) are lined by bile duct-type epithelium, and they may be solitary or multiple; the multiple form may be part of the polycystic disease.

- benign cystic mesothelioma

  • Benign cystic mesothelioma can also be included, a rare neoplasm which may occur in the liver. It is a large, partially cystic, well-encapsulated lesion, characterized by anastomosing cords of tumour cells, separated by large thick-walled vessels, closely reminiscent of a vascular neoplasm.
  • This morphological pattern is quite different from that exhibited by the tumour herein presented. In addition, neoplastic cells of benign cystic mesothelioma are positive to calretinin, HBME-1, and cytokeratins 5/6.

Nota bene: Benign biliary tumours are uncommon, including bile duct adenoma (also known as "peribiliary gland hamartoma"), biliary hamartoma (von Meyenburg complex), biliary cystadenoma, and the solitary bile cysts.

See also

- hepatic cystic lesions