November 25, 2009

Liver Cysts and Tumors

Liver cysts occur in approximately 5% of the population. However, only about 5% of these patients ever develop symptoms. In general, cysts are thin-walled structures that contain fluid. Most cysts are single, although some patients may have several. The symptoms associated with liver cysts include upper abdominal fullness, discomfort, or pain. A small number of patients bleed into the cyst, which causes sudden and severe right upper quadrant and shoulder pain. The bleeding stops on its own, and the pain then improves over the next several days. Liver cysts do not impair the liver’s ability to function. The cyst(s) are usually found by ultrasound (US) or computed tomography (CT scan). Simple liver cysts are always benign. The only patients who require treatment for a liver cyst(s) are those who develop symptoms. Simply removing the fluid from the cyst with a needle is not effective because the cyst fills up again within several days. The best treatment is to remove a large portion of the cyst wall. This surgical procedure can usually be done through the laparoscope, which requires only 2-3 small incisions and an overnight stay in the hospital. Most patients recover fully within 2 weeks. The risk of the cyst recurring is very low. A very small number of patients (0.6% of the general population) have polycystic liver (PLD) disease, which is characterized by the liver appearing like a cluster of very large grapes. Over the course of several years, patients with PLD may develop massive enlargement of the liver, which results in abdominal swelling and discomfort. In extreme cases, the patient may have a very poor quality of life because of the pain and fluid. Unlike the inevitable kidney failure associated with polycystic kidney disease, which can coexist with PLD, PLD does not cause liver failure. The only long-term solution for patients with severe PLD is liver transplantation.
Cystic Tumors
Unlike simple liver cysts, cystic tumors are actually growths that may become malignant over the course of many years. The benign cystic tumor seen most frequently is called a cystadenoma; its malignant counterpart is a cystadenocarcinoma. The symptoms caused by cystic tumors are the same as those seen with simple cysts; fullness, discomfort, and pain. The liver blood tests usually remain normal, unless a cancer has developed. US and CT scans are the best imaging studies to show the cystic tumors, which contain both liquid and solid areas. Because of the possibility of malignancy, cystic tumors must be completely removed surgically with an open (not laparoscopic) operation. The recurrence rate after surgery is very low and the long-term prognosis is excellent.
Benign Tumors
The benign tumors of the liver seen most frequently include cavernous hemangiomas, liver cell adenomas, and focal nodular hyperplasia (FNH). Of these, hemangiomas are by far the most common and occur in about 2% of the population. Hemangiomas are soft, spongy tumors composed of small blood vessels. Most cause no symptoms and they are found incidentally when either an US or CT scan is performed for some other reason. Liver function is not affected and surgical removal is required only in those patients who develop symptoms. Some patients may have pain; rarely, bleeding may occur into the hemangioma. Adenomas occur primarily in women, especially those who take or have taken birth control pills for an extended period of time. The symptoms associated with adenomas include abdominal discomfort and pain. A small percentage of patients may experience spontaneous rupture and potentially life-threatening hemorrhage from the adenoma. The adenomas may also become malignant after several years. As a result of the risk of bleeding and malignant transformation, all adenomas 5 centimeters (2 inches) or larger require surgical removal. In most instances, an open operation is necessary. Focal nodular hyperplasia (FNH) is also a tumor that is found almost exclusively in young women. However, FNH is not associated with birth control pills and rarely causes symptoms. There is no associated risk of either spontaneous rupture or malignancy, as is seen in adenomas. The only patients who require surgical removal are those who have symptoms, or the diagnosis is uncertain; ie, the imaging studies and/or needle biopsy suggest that the tumor may be an adenoma.
Malignant Tumors
Primary Liver Cancer
A cancer that begins in the liver is called a primary liver cancer or hepatocellular carcinoma (HCC). HCC is relatively uncommon in the US. However, HCC is quite common in the Far East and Africa, in part because of the high prevalence of hepatitis B infection in those parts of the world. Cirrhosis from any cause, such as hepatitis or alcoholism, increases the risk of developing a HCC. The spectrum of symptoms seen with HCC vary widely. Some patients feel well and others become quite ill. Liver blood tests are often abnormal, especially if cirrhosis is present. US, CT, and MRI scanning show the tumors. A needle biopsy performed under the guidance of either US or CT may be necessary to confirm the diagnosis. A needle biopsy of the non-tumor bearing portion of the liver is also necessary to see if cirrhosis is present. Surgery offers the only potential cure for patients with HCC. In some patients, the tumor may be removed surgically, if cirrhosis is not present in the remainder of the liver. If cirrhosis is present, the tumor may be ablated (destroyed) with alcohol injection, freezing the tumor (cryotherapy), or heat (Radio Frequency Ablation; RFA). Alcohol ablation is effective in tumors that are less than 5 centimeters in diameter . The procedure is performed by a radiologist under the guidance of either US or CT. Cryotherapy and RFA are surgical procedures that may be performed with either an open operation or laparoscopically. Liver transplantation is also an option in patients with cirrhosis and small (less than 5 centimeters) cancers. If surgery is not an option, other treatments available include either intravenous chemotherapy or chemotherapy directly into the artery feeding the liver. However, neither of these therapies are curative.
Metastatic Tumors
Most cancers that are found in the liver started in another organ, such as the colon, pancreas, stomach, or breast. The presence of metastatic cancer in the liver is usually a sign of an advanced stage of disease and a very limited life expectancy. However, patients with a primary cancer from either the colon, rectum, or a neuroendocrine cancer who do not have cancer outside the liver, may benefit from surgical treatment of liver metastases. Metastases from colorectal cancers are by far the most common encountered in the US. Of the approximately 160,000 patients who develop colorectal cancer annually, about one third will develop liver metastases. Ten percent of these patients may benefit from surgical therapy. Removing a portion of the liver which contains the cancer (liver resection) is the most effective surgical treatment for colorectal metastases. It may be necessary to remove only a small portion of the liver, or the entire right or left half, depending on the size and number of metastases. The patients who have the best results are those who have one or two metastases which are 5 centimeters or less in size and are confined to one lobe of the liver. The 5 and 10 year survivals in these patients are 30% and 20%, respectively. A liver resection is a major operative procedure that carries a 2-3% risk of dying as a result of the operation. Other surgical options to treat metastatic liver cancer include cryotherapy (freezing the tumor) or radio frequency ablation (RFA), which destroys the cancer with heat. Both of these techniques can be performed either open or via the laparoscope. Currently, these two therapies are not felt to be as effective as surgical removal. Patients who are offered cryotherapy or RFA are, for a variety of reason(s), not candidates for surgical resection. The long term survival associated with these two therapies and their role in the treatment of metastatic liver cancer continues to unfold as more follow-up information becomes available.

Adapted from: Cleveland Clinic