Residency · Residency · General Surgery

Management of Liver Masses

Overview

The incidental discovery of liver masses is increasingly common due to widespread use of cross-sectional imaging. The general surgeon must distinguish benign from malignant lesions, understand when observation is appropriate, and determine which lesions require biopsy or resection. The approach is guided by imaging characteristics, clinical context, and underlying liver disease status.

Benign Liver Lesions

Hepatic Hemangioma

Hepatic hemangioma is the most common benign liver tumor, with a prevalence of 5 to 7%. These are cavernous hemangiomas composed of blood-filled vascular spaces lined by endothelium. On imaging, they exhibit characteristic peripheral nodular enhancement on the arterial phase with progressive centripetal fill-in on delayed phases on CT or MRI, while appearing hyperechoic on ultrasound. Hemangiomas are usually asymptomatic and discovered incidentally. Observation is the standard approach, and biopsy is not indicated due to the risk of hemorrhage and because the diagnosis is made radiographically. Surgery is reserved for the rare symptomatic patient (typically with lesions exceeding 10 cm), diagnostic uncertainty, or Kasabach-Merritt syndrome (consumptive coagulopathy). When surgery is performed, enucleation is preferred over formal hepatectomy because hemangiomas have a clear plane from the liver parenchyma. Oral contraceptives and pregnancy have no proven causal link to hemangiomas and are not contraindications.

Focal Nodular Hyperplasia (FNH)

Focal nodular hyperplasia is the second most common benign liver tumor, with a female-to-male ratio of 8:1, typically occurring in women of reproductive age. Pathologically, FNH consists of hyperplastic hepatocytes with a central stellate scar, abnormal bile ductules, and thick-walled arteries. It is not premalignant. On imaging, the central stellate scar is seen in 50 to 80% of cases, and there is intense homogeneous arterial enhancement with isointensity on portal and delayed phases. On MRI with hepatobiliary contrast (Eovist/Primovist), FNH retains the hepatobiliary agent and appears bright on the delayed hepatobiliary phase, which is a key distinguishing feature from hepatic adenoma. Management is observation, with no biopsy needed when imaging is classic. Surgery is only indicated in the rare patient with symptoms, rapid growth, or diagnostic uncertainty. Oral contraceptives do not need to be discontinued.

Hepatic Adenoma

Hepatic adenoma is associated with oral contraceptive use, anabolic steroids, glycogen storage disease, obesity, and metabolic syndrome. These lesions carry risks of hemorrhage (20 to 25%) and malignant transformation (5 to 10%, especially in the beta-catenin mutated subtype). The Bordeaux classification recognizes four subtypes. The HNF1-alpha inactivated subtype (35 to 40% of cases) is steatotic with low malignancy risk and is most common in women on oral contraceptives. The beta-catenin activated subtype (10 to 15%) carries the highest risk of malignant transformation, and resection is recommended regardless of size. The inflammatory subtype (40 to 50%) is telangiectatic, may cause CRP elevation, and carries moderate bleeding risk. The remaining 5 to 10% are unclassified.

Management begins with discontinuation of oral contraceptives and anabolic steroids. An adenoma smaller than 5 cm in a woman can be observed with serial imaging, as it may regress after cessation of oral contraceptives. An adenoma larger than 5 cm warrants resection due to higher hemorrhage and malignancy risk. Any adenoma in a male should be resected regardless of size because of higher malignancy risk. Beta-catenin activated subtypes should be resected regardless of size. For multiple adenomatosis (more than 10 adenomas), liver transplantation may be considered for unresectable disease.

Simple Hepatic Cyst

Simple hepatic cysts are congenital, epithelium-lined, fluid-filled structures with a prevalence of 2 to 7%. Asymptomatic cysts require no treatment and no follow-up imaging. Symptomatic cysts (large, compressive) are managed with laparoscopic fenestration (unroofing or deroofing) with excision of the protruding cyst wall, while the fenestrated cyst base is left in situ. Aspiration alone has near-universal recurrence and is not recommended as definitive treatment. Sclerotherapy with ethanol or tetracycline is reserved for patients unfit for surgery.

Cystadenoma (Mucinous Cystic Neoplasm)

Mucinous cystic neoplasms (cystadenomas) are rare, overwhelmingly affect women, and appear as multiloculated cystic lesions with septations, mural nodularity, and ovarian-like stroma. They are premalignant with risk of transformation to cystadenocarcinoma. They must be distinguished from simple cysts. Management requires complete surgical excision (enucleation or hepatectomy), and fenestration or aspiration must be avoided.

Malignant Liver Lesions

Hepatocellular Carcinoma (HCC)

Hepatocellular carcinoma is the most common primary liver malignancy worldwide, with more than 80% occurring in the setting of cirrhosis (from hepatitis B, hepatitis C, alcohol, NASH, or hemochromatosis). Screening with ultrasound with or without AFP every 6 months is recommended for at-risk patients (those with cirrhosis or chronic HBV). In cirrhotic patients, HCC can be diagnosed without biopsy based on imaging criteria. The LI-RADS classification provides standardized CT/MRI reporting for liver lesions in at-risk patients. Classic imaging features include arterial phase hyperenhancement with washout on portal or delayed phases and threshold growth. LI-RADS 5 indicates definite HCC, LI-RADS 4 indicates probable HCC, and LI-RADS M indicates malignant but not HCC-specific.

The BCLC (Barcelona Clinic Liver Cancer) staging system guides treatment:

BCLC 0/A (very early or early stage) is managed with resection, liver transplant, or ablation. BCLC B (intermediate) is treated with transarterial chemoembolization (TACE). BCLC C (advanced) receives systemic therapy (atezolizumab plus bevacizumab, or sorafenib/lenvatinib). BCLC D (terminal) receives best supportive care.

Surgical Management of HCC

Resection is appropriate for a single lesion with preserved liver function (Child-Pugh A, no portal hypertension). Anatomic resection is preferred for better oncologic outcomes. However, recurrence reaches 70% at 5 years from either intrahepatic metastasis or de novo tumors. Liver transplantation is the definitive treatment for HCC with concurrent cirrhosis. The Milan criteria define transplant eligibility: a single tumor 5 cm or smaller, or up to 3 tumors each 3 cm or smaller, with no vascular invasion and no extrahepatic disease. This achieves 4-year survival of 75% and recurrence below 10%. Extended criteria (UCSF, up-to-seven) allow broader eligibility. Bridging and downstaging with locoregional therapy (TACE, ablation, Y-90) are used while awaiting transplant. Ablation (RFA or microwave) is an option for lesions smaller than 3 cm, where outcomes are comparable to resection, though it is limited by location because proximity to major vessels causes a heat-sink effect.

Intrahepatic Cholangiocarcinoma

Intrahepatic cholangiocarcinoma is the second most common primary liver malignancy, arising from intrahepatic bile duct epithelium. Risk factors include PSC, hepatolithiasis, Caroli disease, and liver flukes (Opisthorchis, Clonorchis). It presents as a mass-forming, periductal infiltrating, or intraductal growth pattern. On imaging, it shows peripheral enhancement with delayed central enhancement due to desmoplastic stroma and may cause capsular retraction. Treatment is hepatectomy with lymphadenectomy (regional nodes in the hepatoduodenal ligament), and a wide negative margin greater than 1 cm is associated with better survival. There is no established role for liver transplant except in highly selected protocols. Adjuvant capecitabine improves survival based on the BILCAP trial.

Hepatic Metastases

The liver is the most common site of metastasis for gastrointestinal malignancies. Colorectal cancer is the most common source (covered in Topic 23). Other sources include neuroendocrine tumors, breast cancer, melanoma, and sarcoma. For neuroendocrine liver metastases, resection or debulking (even if R0 is not achievable) improves symptoms and survival.

Approach to the Incidental Liver Lesion

In a Normal Liver (No Chronic Liver Disease)

For lesions smaller than 1 cm, the vast majority are benign and can be observed, with repeat imaging at 6 to 12 months if needed. For lesions larger than 1 cm, characterization with contrast-enhanced MRI (or multiphase CT) is appropriate. Classic hemangioma or FNH features require no further workup. Indeterminate lesions should undergo hepatobiliary-specific MRI contrast (Eovist/Primovist) or biopsy. Lesions suspicious for adenoma should follow the subtype-specific management algorithm.

In a Cirrhotic Liver (At-Risk Patient)

Any new lesion in a cirrhotic liver should be considered HCC until proven otherwise. Evaluation should follow the LI-RADS classification, and all cases warrant multidisciplinary tumor board evaluation.

Role of Biopsy

Biopsy is not indicated for classic hemangioma, FNH, or HCC meeting LI-RADS 5 criteria. It is indicated for indeterminate lesions, suspected metastatic disease, cholangiocarcinoma, and lymphoma. A coaxial technique should always be used to minimize tract seeding risk. Biopsy of suspected hepatic adenoma should be avoided if resection is planned.

<image>MRI imaging characteristics of common benign liver lesions showing four panels: (1) hemangioma with peripheral nodular enhancement on arterial phase and progressive centripetal fill-in on delayed phase, (2) focal nodular hyperplasia with intense homogeneous arterial enhancement and central stellate scar, (3) hepatic adenoma with arterial enhancement and washout on delayed phase, and (4) simple hepatic cyst appearing uniformly hypointense on T1 and hyperintense on T2 without enhancement. Label the characteristic features in each panel.</image>

<image>Flowchart algorithm for the approach to an incidental liver lesion found on imaging: branching based on liver disease status (normal vs. cirrhotic), lesion size (<1 cm vs. >1 cm), and imaging characteristics. Show pathways leading to observation, further characterization with contrast-enhanced MRI, biopsy, or resection. Include LI-RADS classification pathway for cirrhotic liver and benign lesion criteria for normal liver.</image>

<image>BCLC staging system for hepatocellular carcinoma showing stages 0 through D with corresponding tumor characteristics (number, size, vascular invasion, performance status, liver function) and recommended first-line treatment for each stage: resection/ablation/transplant for stage 0-A, TACE for stage B, systemic therapy for stage C, and best supportive care for stage D.</image>

Clinical Pearls

Hepatic hemangioma is the most common benign liver tumor and should not be biopsied -- the diagnosis is made by characteristic imaging showing peripheral nodular enhancement with centripetal fill-in. FNH retains hepatobiliary contrast agents (Eovist/Primovist), appearing bright on the hepatobiliary phase, which distinguishes it from adenoma, which does not retain contrast. Hepatic adenomas larger than 5 cm or in males should be resected due to higher risk of hemorrhage and malignant transformation. Beta-catenin-activated hepatic adenomas have the highest malignant potential and should be resected regardless of size. HCC can be diagnosed without biopsy in cirrhotic patients when imaging meets LI-RADS 5 criteria (arterial hyperenhancement plus washout plus threshold growth). The Milan criteria (single tumor 5 cm or smaller, or up to 3 tumors each 3 cm or smaller) define transplant eligibility for HCC and achieve the best post-transplant outcomes. Mucinous cystic neoplasms (cystadenomas) must be completely excised -- fenestration or aspiration is inadequate and risks recurrence or malignant transformation. Always consider metastatic disease in a patient with a new liver lesion and a history of extrahepatic malignancy.

References

• European Association for the Study of the Liver. EASL clinical practice guidelines on the management of benign liver tumours. J Hepatol. 2016;65(2):386-398.
• Marrero JA, Kulik LM, Sirlin CB, et al. Diagnosis, staging, and management of hepatocellular carcinoma: 2018 practice guidance by AASLD. Hepatology. 2018;68(2):723-750.
• Nault JC, Bioulac-Sage P, Zucman-Rossi J. Hepatocellular benign tumors -- from molecular classification to personalized clinical care. Gastroenterology. 2013;144(5):888-902.
• Bridgewater J, Galle PR, Khan SA, et al. Guidelines for the diagnosis and management of intrahepatic cholangiocarcinoma. J Hepatol. 2014;60(6):1268-1289.

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