Cyst fluid from a patient with polycystic liver disease was obtained by needle aspiration using ultrasound guidance. The constituents of the fluid resembled the "bile salt-independent" fraction of human bile and supports the hypothesis that such cysts are lined by a functioning, secretory bile duct epithelium.
Polycystic liver disease is a part of the clinical spectrum of hepatic fibropolycystic disease. It has autosomal dominant inheritance and, although expression varies widely, penetrance is virtually complete (1).
The disease predominates in women and is compatible with a long life (2-4). Symptoms tend to occur in the 40s or 50s, and consist of upper abdominal discomfort, fullness, and intermittent pain. Hepatomegaly or abdominal masses may be felt. Usually, liver function tests yield only mild derangement or normal results.
The cysts are considered to be embryologic maldevelopments (5)(6)(7) that "results from the gradual cystic dilatation of groups of persisting intralobular bile ducts which fail to involute in the later embryologic development of the liver" (6) or that arise as an abnormal extension of resorption which is a normal occurrence in the first generation of bile ducts (7).
Since the cysts are lined with cuboidal epithelium that resembles bile ducts (2, 3, 6, 7), studies of the cyst fluid might provide information about the mechanism of cyst formation and the function of isolated bile duct epithelium. In previous studies, performed by injecting materials into the cysts or by giving materials parenterally that are excreted by hepatocytes, the cyst and the biliary tree were found not to communicate (8,9).
In treatment of the patient in the following report, we were encouraged by previous reports (10,ll) to treat the cyst with needle aspiration rather than by surgery, and we collected cyst fluid for study.
A 43-year-old woman was referred for evaluation of a large abdominal mass. A laparotomy that had been previously performed elsewhere and review of the pathological findings confirmed a diagnosis of polycystic liver disease.