Do Liver Cysts Turn Into Cancer?
Liver cysts are thin walled fluid filled sacs that occur in approximately 5% of all individuals. Most of the cysts are benign, but all the cysts possess the ability of turning into malignant cysts. Different cystic lesions of liver include simple cyst, polycystic liver disease, echinococcosis, cystadenoma and cystadenocarcinoma. Although, among these cystic diseases of liver, simple cysts are most common, biliary cystic tumors (biliary cystadenoma and cystadenocarcinoma) can also arise in few individuals. Cystadenoma and cystadenocarcinoma are atypical presentation of cystic tumors as most of the tumors are non-cystic in nature. Thus, in a small subset of people, less than 5% of all liver cyst cases do turn into cancer namely cystadenoma and cystadenocarcinoma, which require specific treatment. This requires early and accurate diagnosis of these lesions as cystadenomas can be misdiagnosed as benign liver cysts, thus potentially delay intervention.
Causes and Risk Factors of Cystic Tumors
Both cystadenoma and cystadenocarcinoma are biliary cyst tumors that arise from biliary epithelium. They are usually slow growing ranging from 1.5 to 35 cm in size. Cystadenomas, just like simple cysts, have congenital predisposition. Cysadenocarcinoma are thought to arise either de novo from formed biliary duct induced by ischemia and carcinogens or from malignant transformation of pre-existing cystadenoma. Studies reveal the predominance of cystadenoma in females (about 90%), cystadenocarcinoma is evenly distributed among men and women. They are mostly seen around 40 to 60 years of age group.
Symptoms of Cystic Tumors
The symptoms of both cystadenoma as well as cystadenocarcinoma tend to be similar to symptoms of simple cysts from being asymptomatic to having abdominal distention, discomfort or pain, shortness of breath, fatigue, back discomfort, nausea, vomiting and early satiety. Along with these symptoms patient might even experience weight loss. Although, complications are rare, they may include obstructive jaundice, cholangitiss, hemorrhage or rupture that are typically related to cystadenoma.
Diagnosis of Cystic Tumors
Laboratory findings such as liver function tests are inconclusive in diagnosing cystic tumors. It is mandatory to differentiate cystic tumors from simple cysts for their early intervention. An ultrasound of cystic tumor will show round or oval shape along with irregular borders, hypoechogenic echo pattern with hyperechogenic septations or papillary projections, wall enhancement and dorsal shadowing due to calcified areas. These patterns are typical of cystic tumors that help differentiate simple cyst with cystic tumors. CT scan and MRI also show similar patterns for cystic tumors; however, it is difficult to differentiate between cystadenoma and cystadenocarcinoma. Contrast enhanced ultrasound may be helpful in differentiating these two tumors from complicated cysts. However, cystadenoma and cystadenocarcinoma can only be differentiated from each other by only surgical specimen, neither ultrasound, CT scan, MRI or fine needle aspiration (FNA) are reliable in definitive diagnosis of these two forms of tumor.
Treatment of Cystic Tumors
The only treatment for cystic tumors, both cystadenoma and cystadenocarcinoma is surgical excision. This is in contrast to simple benign cysts in which only monitoring is required until they become symptomatic or grow in size. The management of cystadenoma is important as they are considered premalignant and have a greater risk of transforming into cystadenocarcinoma in about 20 to 30% cases. Thus, its accurate diagnosis is important along with intervention. Patients with cystic tumors who undergo fenestration have a higher chance of recurrence, as high as 48%. They are of two types: laparoscopic fenestration as well as open fenestration. However, there is a greater chance of recurrence in both laparoscopic (about 33%) and open (about 14%) as compared to hepatectomy. Hepatectomy is a procedure that involves removing the part of liver that is affected by cystic tumor. Surgical removal of a part of liver can be partial or major known as hepatectomy. There is a greater chance of recurrence in patients who undergo partial hepatectomy, with a recurrence rate of 15% as compared to major hepatectomy in which the recurrence rate is about 10%. The recurrence rate of cystadenoma is higher than cystadenocarcinoma.
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