Liver Masses & Hepatic Abscess
Read the enhancement pattern, then leave it, resect it, drain it, or treat it with pills
Benign solid liver lesions
Approach. Most incidental liver masses are benign, and multiphase contrast CT or MRI usually identifies them by enhancement pattern, so biopsy is rarely needed. Patient profile matters: a young woman on oral contraceptives, a man on anabolic steroids, a cirrhotic, and a febrile traveler each point to different lesions.
| Feature | Hemangioma | Focal nodular hyperplasia | Hepatocellular adenoma |
|---|---|---|---|
| Nature | Cavernous vascular malformation; most common benign liver tumor | Hyperplasia around an anomalous artery; second most common | Hormone-driven benign neoplasm |
| Typical patient | Women; incidental | Young women; OCPs not causal | Long-term OCPs, anabolic steroids, glycogen storage disease type I, obesity |
| Imaging | Peripheral nodular enhancement with centripetal fill-in; very bright on T2 | Homogeneous arterial enhancement, central stellate scar that enhances late; retains hepatobiliary-phase contrast | Arterial enhancement, fat or hemorrhage, no scar; dark on hepatobiliary phase |
| Risk | Bleeding if biopsied | None | Rupture; malignant transformation (β-catenin subtype) |
| Management | Nothing if asymptomatic; never biopsy | Nothing; no follow-up | Stop hormones; resect if high risk |
Hemangioma. Usually hyperechoic on ultrasound. Giant hemangiomas can rarely cause pain or consumptive coagulopathy with thrombocytopenia; only symptomatic lesions are enucleated or resected.
Focal nodular hyperplasia. Functioning hepatocytes and bile ductules explain why FNH retains gadoxetate on the hepatobiliary phase, and Kupffer cells explain its uptake of technetium sulfur colloid. It neither bleeds nor turns malignant, and oral contraceptives need not be stopped. Fibrolamellar HCC also has a central scar but strikes adolescents and young adults without cirrhosis and with a normal AFP.
Hepatocellular adenoma. Stop oral contraceptives, estrogen, or anabolic steroids, encourage weight loss, and reimage with MRI. Resect adenomas that remain larger than 5 cm, any adenoma in a man, β-catenin-mutated or growing lesions, and those that bleed; small adenomas in women can be followed. Pregnancy can enlarge adenomas and provoke rupture. A ruptured adenoma with shock is stabilized with resuscitation and transarterial embolization, then resected electively.
Malignant lesions: metastases and HCC
Metastases. The most common malignant liver tumors by far. Colorectal, pancreatic, and gastric cancers reach the liver through the portal vein; breast, lung, and melanoma arrive hematogenously. They are usually multiple and occur in a noncirrhotic liver. Isolated colorectal and neuroendocrine metastases can be resected for cure.
Who gets HCC. Cirrhosis of any cause (hepatitis C, alcohol, MASLD, hemochromatosis) is the main substrate. Chronic hepatitis B causes HCC even without cirrhosis because viral DNA integrates into the host genome, and aflatoxin is a cofactor. Surveil every 6 months with ultrasound, with or without AFP, in all patients with cirrhosis and in high-risk hepatitis B carriers such as Asian men ≥40, Asian women ≥50, and those with a family history of HCC. Hepatitis C without advanced fibrosis and simple steatosis do not warrant surveillance, and hepatitis A never becomes chronic.
- SurveillanceUltrasound ± AFP every 6 months.
- TriggerA nodule ≥1 cm or a rising AFP.
- Multiphase CT or MRIArterial, portal venous, and delayed phases.
- DiagnosisArterial-phase hyperenhancement with washout (± capsule) is HCC (LI-RADS 5); biopsy only if imaging is indeterminate or the liver is not cirrhotic.
- Stage and treatBy tumor burden, liver function, and performance status.
HCC is fed by the hepatic artery, so it lights up in the arterial phase and washes out as portal blood fills the surrounding liver. AFP supports the diagnosis but is neither sensitive nor required, and biopsy adds bleeding and needle-tract seeding risk.
| Option | Best candidate |
|---|---|
| Resection | Solitary tumor, Child-Pugh A, no significant portal hypertension |
| Ablation | Small tumors (≤3 cm); radiofrequency or microwave |
| Transplantation | Within Milan criteria: one tumor ≤5 cm or 2–3 tumors each ≤3 cm, no vascular invasion or extrahepatic spread; cures tumor and cirrhosis |
| TACE | Intermediate-stage, multinodular disease |
| Systemic therapy | Advanced disease: atezolizumab + bevacizumab first line |
Pyogenic and amebic liver abscess
Pyogenic abscess. The most common liver abscess in the US. Sources are the biliary tree (cholangitis, stones, malignant obstruction), the portal vein (diverticulitis, appendicitis), and the bloodstream; many are cryptogenic. Organisms are often mixed (E. coli, Klebsiella, streptococci, anaerobes). Hypervirulent Klebsiella pneumoniae causes monomicrobial abscesses in diabetic and East Asian patients and can spread to the eye (endophthalmitis) and meninges. Patients have fever, RUQ pain, leukocytosis, and a raised ALP; CT shows a rim-enhancing collection.
Treating pyogenic abscess. Image-guided percutaneous aspiration or catheter drainage plus IV antibiotics covering gram-negatives and anaerobes (for example ceftriaxone with metronidazole), for 4–6 weeks in total. Treat the source, such as ERCP for biliary obstruction, and look for colon cancer when no source is found. Surgery is for failed drainage, rupture, or multiloculated abscesses.
Amebic abscess. Entamoeba histolytica cysts are swallowed, trophozoites invade the colon, and they reach the liver through the portal vein. The typical patient is a young man from or returning from Mexico, Central or South America, India, or Africa, with a single right-lobe abscess and often no current diarrhea. Aspirate is odorless brown "anchovy paste," which is liquefied hepatocytes rather than pus, with few trophozoites. Diagnose with ultrasound or CT plus serology, remembering that serology stays positive for years in endemic populations.
Treating amebic abscess. Metronidazole (or tinidazole) kills tissue trophozoites and cures most abscesses without drainage. A luminal agent (paromomycin, a nonabsorbed aminoglycoside, or iodoquinol) must follow to clear intestinal cysts and prevent relapse. Aspirate only for diagnostic doubt, no response after 3–5 days, or a large left-lobe abscess that could rupture into the pericardium.
Hydatid cyst
Biology and diagnosis. Echinococcus granulosus cycles between dogs (definitive hosts) and sheep (intermediate hosts); humans are accidental hosts who swallow eggs from dog feces, typically in sheep-raising regions such as the Mediterranean, Middle East, South America, and Central Asia. (Taenia solium, by contrast, causes cysticercosis of brain and muscle.) A slow-growing, often asymptomatic cyst forms, usually in the right lobe. Imaging shows a well-defined cyst with eggshell wall calcification, daughter cysts, and detached floating membranes (water lily sign); serology and sometimes eosinophilia support it.
Treatment. Albendazole is given before and after either PAIR (puncture, aspiration, injection of a scolicidal agent such as hypertonic saline, re-aspiration) for suitable uncomplicated cysts or surgical cystectomy for complicated, multiseptated, or bile duct-communicating cysts. Communication with the bile ducts contraindicates PAIR because the scolicidal agent can cause sclerosing cholangitis.
Hydatid fluid is highly antigenic. Spillage during casual aspiration or surgery can cause anaphylaxis and seed new cysts, so every procedure is performed under albendazole cover.