Liver tumor

Template:No footnotes Template:Infobox medical condition (new) Liver tumors (also known as hepatic tumors) are abnormal growth of liver cells on or in the liver. Several distinct types of tumors can develop in the liver because the liver is made up of various cell types.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Liver tumors can be classified as benign (non-cancerous) or malignant (cancerous) growths. They may be discovered on medical imaging (even for a different reason than the cancer itself), and the diagnosis is often confirmed with liver biopsy.<ref name=":0" /> Signs and symptoms of liver masses vary from being asymptomatic to patients presenting with an abdominal mass, hepatomegaly, abdominal pain, jaundice, or some other liver dysfunction. Treatment varies and is highly specific to the type of liver tumor.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

Classification

File:Liver tumor types in adults by relative incidence.png

Liver tumor types by relative incidence in adults in the United States.<ref>Template:Cite book</ref>

Liver tumors can be broadly classified as benign or malignant:

Benign

There are several types of benign liver tumors. They are caused by either abnormal growth of neoplastic cells or in response to liver injury, known as regenerative nodules.<ref name=":0" /> One way to categorize benign liver tumors is by their anatomic source, such as hepatocellular, biliary, or stromal.<ref name=":0">Template:Cite book</ref>Template:Rp

Hemangiomas

Cavernous hemangiomas (also called hepatic hemangioma or liver hemangioma) are the most common type of benign liver tumor, found in Template:PercentageTemplate:NdashTemplate:Percentage of people.<ref name=":0" /> They are made up of blood clusters that are surrounded by endothelial cells.<ref name=":3">Template:Cite journal</ref> These hemangiomas get their blood supply from the hepatic artery and its branches.<ref name=":3" /> These tumors are most common in women.<ref name=":3" /> The cause of liver hemangiomas remains unknown; however, it may have congenital and genetic components.<ref name=":3" /> They are not known to become malignant based on the available existing literature.<ref name=":3" />

Liver hemangiomas do not usually cause symptoms.<ref name=":0" /><ref name=":3" /> They are usually small, with sizes up to 10 centimeters.<ref name=":3" /> Their size tends to remain stable overtime.<ref name=":3" /> However, if the hemangioma is large it can cause abdominal pain, a sense of fullness in right upper abdominal area, heart problems, and coagulation dysfunction.<ref name=":0" /><ref name=":3" /> Cavernous hemangiomas are diagnosed with medical imaging (do not usually need biopsy to confirm diagnosis).<ref name=":0" />

Given their benign course and often asymptomatic nature, cavernous hemangiomas are typically diagnosed incidentally (e.g. when medical imaging is obtained for another reason).<ref name=":3" /> In terms of management, they are usually monitored with periodic imaging as well as more closely if the person becomes pregnant.<ref name=":3" /> If the cavernous hemangioma grows quickly or the patient is symptomatic, further medical intervention is warranted.<ref name=":3" /> Therapies include open or laparoscopic surgical resection, arterial embolization, or radio-frequency ablation.<ref name=":3" /> In terms of complications of hepatic hemangiomas, it is very rare for a hepatic hemangioma to rupture or bleed.<ref>Template:Cite journal</ref>

Focal nodular hyperplasia

Focal nodular hyperplasia (FNH) is the second most common benign tumor of the liver.<ref name=":0" /> FNH is found in Template:PercentageTemplate:NdashTemplate:Percentage of adults worldwide.<ref name=":0" /> FNH is more common in females (10:1 female to male ratio) except in Japan and China, in which there is a more equal prevalence of cases between females and males.<ref name=":0" /> FNH is associated with women of childbearing years and has been associated with women taking hormonal oral contraceptives.<ref name=":0" /> This tumor is the result of a congenital arteriovenous malformation hepatocyte response. This process is one in which all normal constituents of the liver are present, but the pattern by which they are presented is abnormal.Template:Citation needed

These tumors usually do not have any symptoms. If large, they may present with abdominal pain.<ref name=":0" /> It is common for patients to have multiple distinct liver lesions; however, they do not tend to grow over time and they do not typically convert to malignant tumors.<ref name=":0" /> Diagnosis is made mainly with medical imaging, such as ultrasound or MRI with contrast.<ref name=":0" /> The majority of FNH have a characteristic "central scar" on contrast-enhanced imaging, which helps to solidify the diagnosis.<ref name=":0" /> However, if a central scar is not present on imaging, it is hard to tell the difference between FNH, hepatic adenoma, and hepatocellular carcinoma, in which cases biopsy is the next step to aid in the diagnosis process.<ref name=":0" />

Given the benign nature of FNH and the fact that they rarely progress in size or undergo malignant transformation, FNH tumors are usually managed with clinical monitoring.<ref name=":0" /> Surgical indications or arterial embolization for FNH include if the FNH lesion is large, symptomatic, or there is uncertainty surrounding the correct diagnosis.<ref name=":0" />

Hepatic adenoma

Hepatocellular adenomas (also called hepatocellular adenoma) are rare benign liver tumors made up of hepatocytes,<ref name=":0" /> with estimates indicating hepatocellular adenomas make up 2% of liver tumors.<ref name=":1">Template:Cite journal</ref> They are most common in women using contraceptives or hormone replacement therapies containing estrogen, women who are pregnant, or people mis-using steroids.<ref name=":1" /> They are also associated with glycogen storage diseases (subtypes I and III), and newer studies are suggesting that diabetes, obesity, high blood pressure, and dyslipidemia are risk factors for hepatic adenomas.<ref name=":1" />

Hepatocellular adenomas are most often asymptomatic and often found incidentally on imaging.<ref name=":1" /> However, if signs and symptoms are present they include non-specific abdominal pain, yellowing of skin, and higher than normal gamma glutamyl transferase and alkaline phosphatase laboratory values.<ref name=":1" /> They are, in most cases, located in the right hepatic lobe and are frequently seen as a single lesion.<ref name=":1" /> Their size ranges from 1 to 30 cm.<ref name=":1" /> They can be difficult to diagnosis with imaging studies alone, because it can be hard to tell the difference between hepatocellular adenoma, focal nodular hyperplasia, and hepatocellular carcinoma.<ref name=":1" /> Molecular categorization via biopsy and pathological analysis aids in both diagnosis and understanding prognosis, particularly because hepatocellular adenomas have the potential to become malignant.<ref name=":0" /><ref name=":1" /> It is important to note, percutaneous biopsy should be avoided, because this method can lead to bleeding or rupture of the adenoma.<ref name=":1" /> The best way to biopsy suspected hepatic adenoma is via open or laparoscopic excisional biopsy.<ref name=":1" />

Because hepatocellular adenomas are so rare, there are no clear guidelines for the best course of treatment.<ref name=":1" /> The complications, which include malignant transformation, spontaneous hemorrhage, and rupture, are considered when determining the treatment approach<ref name=":1" /> Estimates indicate approximately 20-40% of hepatocellular adenomas will undergo spontaneous hemorrhage.<ref name=":1" /><ref name=":0" /> The evidence is not well elucidated, but the best available data suggests that the risk of hepatocellular adenoma becoming hepatocellular carcinoma, which is malignant liver tumor, is 4.2% of all cases.<ref>Template:Cite journal</ref> Transformation to hepatocellular carcinoma is more common in men.<ref name=":0" /> Currently, if the hepatic adenoma is >5 cm, increasing in size, symptomatic lesions, has molecular markers associated with HCC transformation, rising level of liver tumor markers such as alpha fetoprotein, the patient is a male, or has a glycogen storage disorder, the adenoma is recommended to be surgically removed.<ref name=":1" /> Like most liver tumors, the anatomy and location of the adenoma determines whether the tumor can removed laparoscopically or if it requires an open surgical procedure.<ref name=":1" /> Hepatocellular adenomas are also known to decrease in size when there is decreased estrogen or steroids (e.g. when estrogen-containing contraceptives, steroids are stopped, or post-partum).<ref name=":1" />

Women of childbearing age with hepatic adenomas were previously recommended to avoid becoming pregnant altogether; however, currently a more individualized approach is recommended that takes into account the size of the adenoma and whether surgical resection is possible prior to becoming pregnant.<ref>Template:Cite journal</ref><ref name=":1" /> Currently, there is a clinical trial called the Pregnancy and Liver Adenoma Management (PALM) study that is investigating management of hepatic adenomas during pregnancy; however, the results of this trial have not been published as of February 2021.<ref>Template:Cite journal</ref>

Liver Cell Adenomatosis

Liver cell adenomatosis (also called hepatic adenomatosis) is a related but distinct diagnosis from hepatocellular adenoma.<ref name=":2">Template:Cite journal</ref><ref name=":1" /> On medical imaging and histopathological biopsy results they are the same as hepatic adenomas.<ref name=":1" /> Liver cell adenomatosis differs from hepatic adenomas by its definition of more than 10 hepatic adenomas that are in both liver lobes in a person who does not have a glycogen storage disease and is not taking exogenous hormones.<ref name=":1" /> Liver cell adenomatosis is not associated with steroid use (e.g. their size does not change when taking or not taking oral contraceptives containing estrogen or anabolic steroids), which is another distinction from hepatic adenomas.<ref name=":2" /> Liver cell adenomatosis is associated with liver dysfunction and higher rates of bleeding than hepatic adenomas alone.<ref name=":1" /> Available evidence suggests that bleeding occurs in approximately 63% of patients with liver cell adenomatosis.<ref name=":2" /> Liver cell adenomatosis is also associated with becoming hepatocellular carcinoma.<ref name=":2" /> Like hepatic adenomas, they are diagnosed with imaging and biopsies as needed. Treatment of liver cell adenomatosis is difficult due to the multiple, widespread lesions. Liver imaging should be reviewed to see if it is possible to surgically remove the tumors.<ref name=":1" /> Liver transplantation is a treatment option for some patients.<ref name=":1" />

Simple Liver Cysts

Liver cysts are common. They are fluid-filled contained structures within the liver. Simple liver cysts are seen most commonly in women and kids.<ref name=":0" /> In terms of pathophysiology, they are formed in response to developmental events and in response to trauma and inflammation.<ref name=":0" /> In addition, liver cysts can be seen with polycystic kidney disease and echinococcosis infection (hydatid disease).<ref name=":0" /><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

Pseudotumors:

Pseudotumors differ from liver tumors in that they are not a proliferation of abnormal cells but are "local variations" of tissue type.<ref name=":0" /> Notably, liver pseudotumors can be confused for a liver tumor on initial imaging studies when diagnostically working up a liver mass.<ref name=":0" /> Examples of pseudotumors include: distinct areas of hepatic fibrosis, pockets of fatty liver changes, and inflammatory pseudotumor.<ref name=":0" />

Cancerous

File:Ultrasound Scan ND 1230124453 1300210.png

Large HCC filling almost entire of right lobe

File:Secondary tumor deposits in the liver from a primary cancer of the pancreas.jpg

Cross section of a human liver, showing multiple large pale tumor deposits. The tumor is an adenocarcinoma derived from a primary lesion in the body of the pancreas.

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• Most cases are metastases from other tumors, frequently of the GI tract (like colon cancer, carcinoid tumors mainly of the appendix, etc.), but also from breast cancer, ovarian cancer, lung cancer, renal cancer, prostate cancer, etc.
• The most frequent, malignant, primary liver cancer is hepatocellular carcinoma.<ref>Template:Cite journal</ref>
• Other forms of primary forms of liver cancer include cholangiocarcinoma, mixed tumors, sarcoma, and hepatoblastoma.

Diagnosis

Template:See Upon discovery of a liver tumor, the main issue in the workup is to determine whether the tumor is benign or malignant. Many imaging modalities are used to aid in the diagnosis of malignant liver tumors. These include sonography (ultrasound), computed tomography (CT) and magnetic resonance imaging (MRI).

Tumor markers, chemicals sometimes found in the blood of people with cancer, can be helpful in diagnosing and monitoring the course of liver cancers. High levels of alpha-fetoprotein (AFP) in the blood can be found in many cases of HCC and intrahepatic cholangiocarcinoma. Cholangiocarcinoma can be detected with these commonly used tumor markers: carbohydrate antigen 19-9 (CA 19–9), carcinoembryonic antigen (CEA) and cancer antigen 125 (CA125). These tumour markers are found in primary liver cancers, as well as in other cancers and certain other disorders.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>

Ultrasound

{{#invoke:Labelled list hatnote|labelledList|Main article|Main articles|Main page|Main pages}} Ultrasonography of liver tumors involves two stages: detection and characterization.Template:Citation needed Tumor detection is based on the performance of the method and should include morphometric information (three axes dimensions, volume) and topographic information (number, location specifying liver segment and lobe/lobes). The specification of these data is important for staging liver tumors and prognosis.Template:Citation needed Tumor characterization is a complex process based on a sum of criteria leading towards tumor nature definition. Often, other diagnostic procedures, especially interventional ones are no longer necessary. Tumor characterization using the ultrasound method will be based on the following elements: consistency (solid, liquid, mixed), echogenicity, structure appearance (homogeneous or heterogeneous), delineation from adjacent liver parenchyma (capsular, imprecise), elasticity, posterior acoustic enhancement effect, the relation with neighboring organs or structures (displacement, invasion), vasculature (presence and characteristics on Doppler ultrasonography and contrast-enhanced ultrasound (CEUS).Template:Citation needed

Computed tomography

File:Late arterial and portal venous phase CT of focal nodular hyperplasia.jpg

Selected images from a biphasic CT of Focal Nodular Hyperplasia in the left hepatic lobe (arrow). These masses have characteristic early arterial enhancement (6a) with contrast wash out on the portal venous phase images (6b) from the mass making these lesions difficult to identify on portal venous phase images alone.Template:Citation needed

When evaluating hepatic masses by abdominal computed tomography (CT), it can be advantageous to have both late arterial and portal venous phase images since some tumors enhance briskly during the arterial phase (hepatocellular carcinoma, hepatic adenoma, follicular nodular hyperplasia (FNH), and hypervascular metastasis), but maybe occult or difficult to characterize on portal venous phase imaging alone. However, it should be stressed that the addition of late arterial phase images is only indicated if one of these tumors is suspected, or if there is a need for further characterization of a hepatic mass, since the large majority of patients will not benefit from the addition of this phase. In addition, if there is a need to definitively characterize a hepatic mass, MRI is generally more sensitive and specific, with no associated radiation dose.Template:Citation needed

External links

• Liver cancer at Mayo Clinic