Special Surgery 12. Benign Tumors of the Liver: Symptoms, Differential Diagnosis, Treatment

I. General Approach and Differential Diagnosis

Main Lesions

1. Cystic lesions: simple cyst, polycystic liver disease, hydatid cyst
2. Hepatic hemangioma
3. Focal nodular hyperplasia (FNH)
4. Hepatocellular adenoma (HCA)

• Most benign liver lesions are incidental on US/CT/MRI
• Most are asymptomatic and need no surgery if diagnosis is certain
• Symptoms occur with large size, compression, bleeding, rupture or infection

Clinical Features and Red Flags

• Usually asymptomatic
• Possible symptoms: RUQ/upper abdominal pain, fullness, early satiety, palpable mass if large
• Acute pain + hypotension → bleeding adenoma or ruptured lesion
• Fever → infected cyst, abscess or hydatid complication
• Jaundice is uncommon; suggests biliary compression or another diagnosis

Differential Diagnosis and Workup

• Important differentials: HCC, intrahepatic cholangiocarcinoma, liver metastases, abscess, hydatid cyst
• History: known cancer, cirrhosis/hepatitis, oral contraceptives, anabolic steroids, pregnancy, Echinococcus exposure
• Labs usually normal in incidental benign lesions
• AFP if HCC is possible; CEA/CA 19-9 if metastasis or biliary/cystic neoplasm is possible
• Eosinophilia + Echinococcus serology if hydatid cyst suspected
• Imaging: US first, then contrast-enhanced US, multiphasic CT or MRI for characterization
• Avoid biopsy of typical hemangioma and suspected hydatid cyst

II. Cystic Lesions of the Liver

Non-Parasitic Cysts

1. Simple Liver Cyst

• Benign fluid-filled cyst, usually congenital biliary lesion
• Usually incidental and asymptomatic
• US: anechoic, thin wall, posterior enhancement, no septa/solid component
• Treatment: no treatment if asymptomatic and typical
• Symptomatic large cyst → laparoscopic fenestration / deroofing
• US-guided aspiration/drainage ± sclerotherapy: selected cases; aspiration alone recurs often
• Resection if cystic neoplasm cannot be excluded

2. Polycystic Liver Disease

• Multiple hepatic cysts; can be isolated or associated with polycystic kidney disease
• Liver function usually preserved, even with large liver
• Symptoms: abdominal distension, pain, early satiety, reflux, dyspnea from mass effect
• Treatment: observation if asymptomatic
• Dominant symptomatic cyst → US-guided drainage/aspiration + sclerotherapy
• Multiple superficial symptomatic cysts → laparoscopic/open fenestration
• Liver transplantation: rare; severe diffuse disease with impaired function, portal hypertension, malnutrition or disabling symptoms

Parasitic Cysts: Echinococcus / Hydatid Cyst

• Caused mainly by Echinococcus granulosus
• Liver is the most common involved organ
• Often asymptomatic for years; may cause RUQ pain/fullness or hepatomegaly
• Complications: biliary compression, cholangitis, rupture, secondary infection, peritoneal spread, anaphylaxis

Diagnosis

• US: cyst membranes, daughter cysts, hydatid sand depending on stage
• CT/MRI: size, anatomy, calcification, relation to vessels/bile ducts
• ELISA/serology supports diagnosis
• Eosinophilia can occur but is not always present

Treatment

• Albendazole preferred; mebendazole alternative
• PAIR in selected uncomplicated active cysts: puncture → aspiration → injection of hypertonic saline/scolicidal agent → re-aspiration
• Surgery: pericystectomy/cystectomy, partial hepatectomy selected, drainage if biliary communication
• Key principle: avoid spillage → prevents recurrence and anaphylaxis

III. Solid Benign Liver Tumors

Hepatic Hemangioma

• Most common benign liver tumor
• Benign vascular lesion from endothelial-lined blood-filled spaces / vascular malformation
• Female predominance; often incidental
• Usually asymptomatic
• Large lesions: RUQ discomfort, fullness, early satiety, compression symptoms
• Rare complications: rupture/bleeding, Kasabach-Merritt syndrome

Diagnosis and Differential

• US: often well-defined hyperechoic lesion
• Contrast CT/MRI/CEUS: peripheral nodular enhancement → centripetal fill-in
• MRI useful for atypical lesions; blood-pool scintigraphy historical/selected for larger lesions
• No biopsy if typical hemangioma
• Differential: metastasis, HCC, FNH, adenoma

Treatment

• No treatment if asymptomatic and diagnosis is secure
• Surgery only if symptomatic, rapidly growing, compressive, bleeding/complicated or diagnosis remains uncertain
• Options: enucleation or resection; embolization selected for bleeding/high-risk cases

Focal Nodular Hyperplasia (FNH)

• Benign hyperplastic hepatocyte nodule in normal liver
• Response to arterial/vascular malformation
• Second most common benign solid liver tumor
• Female predominance; usually young women
• Usually asymptomatic; occasional vague abdominal discomfort
• No malignant transformation in typical FNH

Diagnosis and Differential

• CT, MRI or contrast-enhanced US
• Typical finding: central scar, especially in larger lesions
• MRI has best diagnostic performance
• Differential: hepatocellular adenoma, HCC, hypervascular metastasis

Treatment

• No treatment if asymptomatic and diagnosis is certain
• Follow-up usually not needed for typical FNH
• OCP/pregnancy association is weaker than adenoma; stopping OCP is not routinely required for typical FNH
• Surgery only if symptoms are clearly caused by FNH or diagnosis remains uncertain after expert imaging

Hepatocellular Adenoma (HCA)

• Rare benign epithelial tumor of hepatocytes
• Important because of bleeding/rupture and rare malignant transformation
• Female predominance, but higher malignant risk in men
• Risk factors: oral contraceptives/estrogen, pregnancy, anabolic steroids, obesity/metabolic syndrome, glycogen storage disease
• Symptoms: often asymptomatic; upper abdominal pain if bleeding or large
• Intratumoral/intracapsular bleeding → acute pain
• Rupture → hemoperitoneum and shock
• Risk of rupture increases above 5 cm
• Malignant transformation risk: beta-catenin activation and male sex

Diagnosis and Differential

• Multiphasic MRI preferred; CT useful for hypervascular lesion and bleeding
• MRI can suggest some subtypes, but beta-catenin activation cannot be reliably excluded by imaging alone
• Biopsy only after specialist MDT discussion if diagnosis/subtype remains uncertain
• Differential: FNH, well-differentiated HCC, hypervascular metastasis, hemangioma

Treatment

• Stop oral contraceptives / anabolic steroids
• Weight loss and metabolic risk correction
• Women: observe after risk-factor withdrawal; resect if lesion remains >= 5 cm or grows
• Men: resection generally recommended regardless of size
• Resect proven beta-catenin activated adenoma
• Resect if symptomatic, ruptured/bleeding, uncertain diagnosis or suspected malignant transformation
• Bleeding adenoma: transarterial embolization first if available, then delayed resection if indicated

IV. Treatment Summary / Exam Focus

Observation Is Usually Enough

• Typical asymptomatic simple cyst
• Typical asymptomatic small hemangioma
• Typical asymptomatic FNH with secure diagnosis
• Small HCA in woman after hormonal/risk-factor withdrawal if stable and no high-risk features

When Intervention Is Needed

• Simple cyst / polycystic liver: symptomatic compression → drainage/sclerotherapy or fenestration; transplantation only rare severe diffuse disease
• Hydatid cyst: albendazole + PAIR or surgery depending on stage/size/location; avoid spillage/anaphylaxis
• Hemangioma: surgery only for symptoms, rapid growth, compression, bleeding or uncertain diagnosis
• FNH: surgery only for clear symptoms or uncertain diagnosis
• HCA: stop hormones/steroids; resect male, beta-catenin, >=5 cm, growing, symptomatic, bleeding/ruptured or suspicious lesions