eMedicine Specialties > Radiology > Gastrointestinal

Biliary Cystadenoma/Cystadenocarcinoma

Author: Mohammad Alobaidi, MD, Diagnostic Radiologist, River Oaks Imaging and Diagnostics, Spencer Radiology
Coauthor(s): Ali Shirkhoda, MD, Director, Division of Diagnostic Imaging, William Beaumont Hospital; Clinical Professor of Radiology, University of California in Irvine and Wayne State University
Contributor Information and Disclosures

Updated: Dec 18, 2008

Introduction

Background

Biliary cystadenoma represents a rare benign cystic hepatic neoplasm that has premalignant potential. The tumor originates in the bile ducts and is lined by mucin-secreting columnar or cuboidal epithelium. Biliary cystadenoma can appear as a unilocular or multilocular cystic intrahepatic mass. The malignant counterpart is biliary cystadenocarcinoma, which is believed to arise from the premalignant form.^1,2,3,4

Both biliary cystadenoma and cystadenocarcinoma are slow growing; as a result, they can be difficult to distinguish from simple hepatic cysts, especially when the tumors are in the unilocular form. The diagnosis is often difficult because the clinical presentation is also similar to that of hepatic cysts. Moreover, other hepatic cystic lesions, including hydatid cysts and a number of metastatic tumors that undergo cystic degeneration, can mimic biliary cystadenomas and cystadenocarcinomas. The radiographic appearances of benign and malignant cystic intrahepatic lesions overlap significantly.

Related eMedicine topics:

Hepatic Cystadenomas

Pancreas, Serous Cystadenoma

Bile Duct Tumors

Frequency

International

Approximately 100 cases of cystadenomas and 50 cases of cystadenocarcinomas have been reported worldwide. These lesions account for less than 5% of all patients with intrahepatic cysts.⁵ Approximately 85% of cystadenomas and cystadenocarcinomas are found in the intrahepatic portions of the biliary ducts, whereas 15% are in the extrahepatic ducts. A slight predilection is seen for the right hepatic lobe; however, lesions have been found in both hepatic lobes in as many as 25% of patients.

Mortality/Morbidity

• Recurrence of biliary cystadenomas and malignant transformation is possible.
• Patients usually have no significant or contributory comorbidities; however, potential complications, such as rupture of the tumor into the peritoneum or penetration into the diaphragm, can significantly alter morbidity.
• With the rare extrahepatic tumor, biliary obstruction and dilatation may occur.

Race

Biliary cystadenocarcinoma occurs more frequently in whites than in other races.

Sex

• Benign cystadenomas affect females more than males, with a reported female-to-male ratio of 4:1.
• The ovarian stroma type is found exclusively in females.
• Malignant cystadenocarcinomas affect males and females equally.

Age

Biliary cystadenoma is found mostly in those who are middle-aged, with a peak incidence in people aged 40-50 years. More than 75% of patients are older than 30 years.

Presentation

Presentation and natural history

Grossly, biliary cystadenomas and cystadenocarcinomas are usually multilocular cysts that have internal septa and nodularity of the inner wall. In one study, the presence of septa without nodularity was seen only in cystadenomas. The internal fluid content of the cystic cavity often consists of a high-molecular-weight glycoprotein called mucin. However, hemorrhagic, bilious, clear, and mixed-fluid contents have also been observed.

Histologically, biliary cystadenomas and cystadenocarcinomas are lined by cuboidal or columnar epithelium and are surrounded by dense collagenous tissue. The tumor cells are well differentiated and have malignant predisposition with invasion of the basement membrane. More aggressive tumors penetrate the surrounding hepatic parenchyma or even the diaphragm. The collagenous tissue surrounding the cavity is lined by inflammatory cells and, occasionally, by lipid-laden macrophages. The lesions are similar to mucinous cystic tumors in that they arise in the pancreas and ovaries.

Hytiroglou et al reported a case in which cystadenocarcinoma of the liver with 2 histologic cell types was described.⁶ One cell type contained clear cytoplasm with mucin, whereas the other cell type contained eosinophilic cytoplasm that displayed hepatocytic features, indicating that biliary cystadenomas may contain a subpopulation of tumor cells with a hepatocytic appearance that was previously unknown. This observation demonstrates a possible practical application of immunohistochemical staining to differentiate hepatocellular carcinoma from biliary cystadenocarcinoma.

Cystadenocarcinomas have been divided into 2 subgroups based on pathologic and histologic features that determine the patient's prognosis. The presence of ovarian stroma in females is believed to be a better prognostic indicator,⁷ although differentiation based on morphology is not reliable. Furthermore, immunohistochemical analysis has been used to differentiate cystadenocarcinomas in patients with a favorable outcome from cystadenocarcinomas in patients with a poor outcome.^8,9  

Several mucin core protein genes have been isolated, including MUC1, which is expressed in invasive ductal carcinomas of the pancreas and invasive cholangiocarcinomas; MUC1 is associated with a poor prognosis.^8,9  MUC2 expression, however, is associated with a better prognosis and is expressed in intraductal papillary mucinous tumors of the pancreas, as well as in biliary cystadenocarcinomas.

Most patients with benign developmental cystic disease are asymptomatic, and the disease is discovered incidentally, although approximately one third of patients complain of right upper quadrant abdominal discomfort. In 25% of patients with benign disease, hepatomegaly is noted on physical examination. Abdominal swelling, dyspepsia, nausea, and vomiting are other nonspecific findings in patients with benign or malignant lesions. Obstructive jaundice is extremely unusual in benign cystic diseases and, if present, should raise a clinical suspicion of neoplasm.

The differential diagnoses for a patient who presents with an upper abdominal mass and pain include cystic lesions, solid neoplasms, and lesions resulting from trauma.^10,11,12,13 The workup of patients with hepatic cysts should begin with laboratory evaluation; liver function findings are usually normal, and red blood cell and white blood cell counts should be obtained to exclude anemia or infection.

When a lesion is diagnosed as benign, both clinical and radiologic findings are used to obtain a degree of certainty in the diagnosis. Short of tissue biopsy, the clinician and radiologist must interpret findings within the appropriate clinical context. This interpretation is more difficult if a cystic lesion is identified in a patient with a previously known malignancy.

Treatment

The most difficult decision that needs to be made is whether intervention is needed in the patient who has a hepatic cyst. If malignancy is suspected and if the radiologic findings are equivocal, then the diagnosis must be made by tissue analysis. A tissue sample is usually obtained surgically, although some centers may attempt image-guided biopsy. The possible risk for hemorrhage with image-guided biopsy is a result of the vascular nature of the liver. The major indications for surgery are pain, rupture, hemorrhage, infection, and a strong suggestion of malignancy.

The accepted definitive treatment for biliary cystadenoma and cystadenocarcinoma is surgical resection. No surgical distinction is made between cystadenoma and its malignant counterpart because cystadenomas are at risk for malignant degeneration. Thus, surgical intervention is identical for cystadenoma and cystadenocarcinoma. Recurrence, malignant transformation of biliary cystadenoma into cystadenocarcinoma, or both are major indications for total surgical excision.

The decision to resect the lesion should be based on the overall patient surgical suitability. Factors include the patient's age and comorbidities, the likelihood of anatomic resectability, and the patient's hepatic function status. Unlike hypervascular hepatocellular carcinoma, selective nonsurgical treatments, such as hepatic artery ligation, arterial embolization, and tumor injection, are not options in biliary cystadenoma and cystadenocarcinoma because these lesions are generally avascular or hypovascular. Even in the setting of surgical resection, recurrence is common; biliary cystadenocarcinomas have a relatively high recurrence rate after total surgical cystectomy.

Medical treatment has no role in cases of biliary cystadenoma or cystadenocarcinoma. In the rare patient who has a cystic hepatic lesion of uncertain etiology or of malignant potential, the clinician's decision to observe the lesion or to resect is difficult to make. Indications for resection of lesions with equivocal findings include pain, hemorrhage, rupture, and infection.

Preferred Examination

Diagnostic imaging is an integral part of the patient evaluation for cystic lesions in the liver. Although the 3 primary imaging modalities are ultrasonography, computed tomography (CT) scanning, and magnetic resonance imaging (MRI), ultrasonography should be the initial screening modality. However, CT scanning and, occasionally, MRI may be needed to determine the exact location and extent of the disease.

Limitations of Techniques

In general, all 3 imaging modalities have inherent limitations. In published studies, CT scanning was less sensitive in correctly identifying septa within a cystic lesion.^14,15,16 Ultrasonography is more reliable in correctly diagnosing the degree of septation, which is a predominant feature of both cystadenomas and cystadenocarcinomas. Papillary projections can be seen with both CT scanning and ultrasonography.

MRI signal characteristics of biliary cystadenoma/cystadenocarcinoma are not specific for the disease. The cyst often appears hypointense on T1-weighted images and hyperintense on T2-weighted images, similar to other fluid-filled cystic lesions. Furthermore, depending on the fluid content of the cyst, the T1- and T2-signal characteristics can vary.

Differential Diagnoses

Autosomal Dominant Polycystic Kidney Disease
Choledochal Cyst
Hepatic Adenoma
Hepatocellular Carcinoma
Liver, Metastases

Other Problems to Be Considered

Abscess
Cystic echinococcosis
Cystic sarcoma
Hematoma
Hydatid cysts
Mesenchymal hamartoma
Old pyogenic abscess
Simple congenital hepatic cysts

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