Benign Liver Tumors

Evaluation

1. History, Physical Exam, Lab Tests
• most benign tumors are clinically silent and are found incidentally on US or CT scan for other indications
• risk factors for hepatocellular carcinoma should be excluded: cirrhosis, chronic hepatitis
• must also exclude a prior extrahepatic malignancy
• symptoms to note include abdominal pain, weight loss, early satiety
• physical exam should detect signs of chronic liver disease, palpable liver mass, or other malignancy
• lab studies should check for anemia, liver function, and tumor markers (AFP, CEA, CA 19-9)


2. Imaging
• cross-sectional imaging is the mainstay of diagnosis
• major tools are contrast-enhanced MRI and CT
• scans should be done with liver protocol: precontrast, early arterial phase, portal venous phase, and equilibrium phase
• cystic versus solid is the first step in radiographic assessment
• solid lesions can be further characterized by their enhancement pattern on postcontrast imaging
• with contemporary imaging, the need for liver biopsy to establish a diagnosis is uncommon

Benign Lesions

1. Simple Cysts




• simple cysts contain serous fluid, do not communicate with the biliary tree, and do not have septations
• complicated cysts suggest a biliary neoplasm: cystadenoma or cystadenocarcinoma
• occur in 5% of adults
• can be very large (up to 20 cm)
• usually are asymptomatic incidental findings on imaging
• if a patient is symptomatic, one must consider other sources for the symptoms before attributing them to the cyst
• most common symptoms are from mass effect: early satiety from duodenal or gastric compression
• most common complication is intracystic hemorrhage, which rarely is life-threatening


1. Management
• asymptomatic cysts do not require treatment or serial follow up
• needle aspiration should only be used to document a symptomatic response since the cyst will always recur
• there is no evidence documenting long-term effectiveness of aspiration and sclerotherapy
• laparoscopic fenestration of the cyst is the treatment of choice, which involves excising the cyst wall just above its margin with the liver



2. Hemangioma
• most common benign neoplasm of the liver
• no risk of malignant degeneration
• very small risk of rupture or bleeding


1. Clinical Manifestations
• most are incidentally found and are asymptomatic
• large lesions (> 10cm) can cause pain or mass effect symptoms
• giant cavernous hemangiomas can cause a DIC-type picture
• in the pediatric population, high-output cardiac failure from arteriovenous shunting can result


2. Diagnosis
• multiphasic (liver protocol) CT or MRI is definitive
• typical characteristics include peripheral pooling of early phase contrast in the lesion, followed by centripetal enhancement on later portal venous phase images
• biopsy is contraindicated because of the bleeding risk


3. Management
• asymptomatic lesions can be observed, regardless of size
• for symptomatic lesions, enucleation is often technically possible
• anatomic resection may be necessary in some cases
• arterial embolization can be used preoperatively to shrink the lesion or as definitive treatment in high-risk patients


3. Focal Nodular Hyperplasia


1. Clinical Manifestations
• 2^nd most common benign solid tumor of the liver
• may be a hyperplastic reaction to a congenital vascular malformation
• most common in young women (90%)
• oral contraceptives do not appear to be a risk factor
• no malignant potential
• do not rupture or bleed
• AFP is normal
• characterized by a central scar containing a large artery with multiple branches radiating through the fibrous septa to the periphery of the lesion
• majority < 5 cm
• typically discovered incidentally on imaging or during laparoscopy


2. Diagnosis
• FNH typically shows strong hypervascularity in the arterial phase of CT or MRI with a central nonenhancing scar
• enhancement fades over time and becomes isointense to the liver parenchyma in the portal and delayed phases
• on delayed imaging, the central scar may become hyperdense as contrast diffuses into the fibrous center of the mass
• if no central scar is seen (15%), distinction between adenoma or fibrolamellar carcinoma can be impossible
• since FNH contains Kupffer cells, radiolabeled sulfur colloid scans are positive in 60% of FNH patients, and can be used in difficult to diagnose cases
• CT-guided biopsy usually reveals normal liver or suggests cirrhosis



3. Management
• asymptomatic patients with typical imaging findings of FNH do not need resection or long-term follow up
• no need to stop OCPs
• inability to rule out malignancy is the most common indication for surgery


4. Hepatic Adenoma



1. Clinical Characteristics
• occurs most commonly in women between ages 20 – 40
• strong association with long-term OCP use
• anabolic steroid use is a risk factor for men
• familial adenosis polyposis and glycogen storage diseases are genetic syndromes associated with HCA
• major risks of HCA are rupture, necrosis, and malignant degeneration


2. Symptoms
• most patients present with symptoms (50% - 75%)
• upper abdominal pain is common and may be related to hemorrhage into the tumor or local compressive symptoms
• some patients may present acutely with rupture or intraperitoneal hemorrhage


3. Diagnosis
• AFP is normal unless there is malignant transformation
• on CT, adenomas have peripheral enhancement during the arterial phase, centripetal progression during the portal phase, and become isodense during the late phase
• MRI typically reveals a well-demarcated heterogenous mass containing fat or hemorrhage with arterial phase enhancement


4. Classification
• HCAs can be subtyped based on their genotype
• the highest risk of malignancy is seen in adenomas with activating mutations in β-catenin
• preoperative biopsy and genetic analysis may become useful diagnostic and therapeutic tools in the future


5. Management
1. Intra-abdominal Hemorrhage
• embolization will usually control the acute hemorrhage, followed by elective resection
• if embolization is unsuccessful or unavailable, then an emergency operation is necessary, and should be approached like a trauma laparotomy
• pringle maneuver, packing, selective hepatic arterial ligation are all possible options for controlling bleeding
• resection should not be attempted in unstable patients
• in tumors ≥ 5 cm, risk of rupture is 30% - 50%


2. Indications for Elective Resection
• symptomatic lesions
• inability to rule out malignancy
• size larger than 5 cm
• margin status is not important, and limited resections can be performed


3. Asymptomatic Adenomas < 5 cm
• discontinue OCPs
• reimage with MRI in 6 months
• regression may occur after discontinuing OCPs
• resection is necessary if the lesion increases in size by 20% or becomes larger than 5 cm


1. Pregnancy
• pregnancy is not contraindicated in women with adenomas < 5 cm
• since the behavior of adenomas during pregnancy is unpredictable, some surgeons will recommend elective resection before pregnancy
• most surgeons will monitor the lesion with serial ultrasounds every 6 – 12 weeks during pregnancy, and only recommend surgery if the lesion increases by more than 20% or becomes larger than 5 cm