Causes and risk factors
The cause of neoplasms is probably the presence of ectopic embryonic tissue (that is, not in the place where it should be located physiologically) with the characteristics of ovarian tissue. The presence of mesenchymal tissue in the cyst is a risk factor for the degeneration of biliary cystadenoma into cystadenocarcinoma, a malignant variant of cystadenoma.
Which are the symptoms?
Usually the following symptoms appear: abdominal pain and a feeling of compression (mass-effect, namely, the effect exerted by pathologically enlarged tissue (tumor) on neighboring healthy tissues). On the other hand, clinical and laboratory signs of jaundice and cholangitis suggest the presence of biliary tract obstruction. Serum tumor markers are usually normal and therefore cannot be used to distinguish biliary cystadenoma from a simple cyst, while the analysis of markers in cystic fluid seems to have diagnostic significance.
As a rule, neoplasms grow slowly, but are considered precancerous with a potential risk of malignant transformation (about 30%).
How is it diagnosed?
Differential diagnosis is often difficult, especially for other liver cyst formations (simple cyst and echinococcal cyst), but it is important since liver cystadenoma requires radical resection to prevent the risk of enlargement (and, thus, complications, such as rupture and infection), relapse (90% with incomplete removal), and malignant degeneration (30%). Sometimes the diagnosis of cystadenoma is detected unexpectedly (i.e., by accident). The diagnosis is made during a histological evaluation of the cyst wall, which was considered a simple cyst during the preoperative evaluation and therefore undergoes fenestration.
The differential diagnosis includes simple liver cysts, echinococcal cysts, liver abscesses, cystic malignances, Karolyi’s disease, and polycystosis.
Routine radiological examinations (ultrasound, CT, and MRI) are an important diagnostic tool. Typical signs include the presence of multiocular cystic neoplasms with internal septs, a thickened and uneven surface, nodules in the walls with protruding papillae, calcification and enlargement of the walls.
Ultrasonography is usually more sensitive to the presence of septa, while CT is always necessary to assess the relationship of the lesion with vascular structures in the parenchyma.