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Everything you need to know about Computed Tomography (CT) & CT Scanning

Imaging Pearls ❯ Liver ❯ Nonmalignant Tumors

  • Approach to small hepatic hypodensities
    - Jones et al looked at 1454 outpatients with a contrast-enhanced CT
    - 17% had a TSTC (< 15 mm)
    - In patients without a known malignancy, 100% were benign
    - Schwartz et al looked at CT scans for 2978 patients with cancer
    - 12.7% had a TSTC
    - 80% were benign
    - 12% were malignant
    - TSTC’s metastatic in 22% of breast cancer patients
  • Metastases
    1. Most common site of solid organ metastases
    2. Most common hepatic metastases are hypovascular
    3. Most common lesions
    - Colon, lung, breast, pancreas, neuroendocrine, melanoma, stomach
    4. 50% of colorectal cancer patients
  • Hepatic Cysts vs Metastases: “Federle Pearls”
    - Small hypodense lesion (<2 cm) in a non-cancer patient is nearly always benign
    - Lesion less than blood density on unenhanced CT is almost always benign
    - Either cyst, biliary hamartoma, or thrombosed (hyalinized) hemangioma
  • Biliary Hamartomas: Facts
    - Bile duct adenoma, von Meyenburg complex
    - Benign proliferation of bile ductules and stroma
    - Small (1-10 mm), few to innumerable
    - Probably a common cause of small low density lesions
    - Common in pts with fibro-polycystic disease (liver + kidneys)
  • Biliary Cystadenomas: Facts
    - Large, solitary, complex multiseptated cystic mass
    - Should be considered malignant or premalignant
    - Much less common than other cystic masses
    - Almost exclusively in women
  • Benign Hepatic Masses May Arise Together (Federle Pearl)
    - Cavernous hemangiomas and cysts
    - Probably random, both common
    - Cavernous hemangiomas and FNH
    -  Not random
    - 20% of pts with FNH also have hemangiomas
    - (only 9% of pts with other benign masses have hemangioma also)
    - FNH and adenoma
    - Probably not random
    - FNH common in any vascular disturbance of liver, congenital or acquired
    - Vilgrain et al: Radiology 2003; 229:75-79
  • Federle’s FNH vs Hepatic Adenoma Pearls
    - Common
    - Uniformly hypervascular
    - Central scar (larger ones)
    - Pseudocapsule (draining veins)
    - Calcification very rare
    - Focal fat = rare
    - Hemorrhage very rare
    - Usually solitary
    - Uncommon
    - Heterogeneously hyper
    - No central scar
    - Capsule (in ~25%)
    - Focal calcifications (~10-20%)
    - Focal fat + hemorrhage common (especially  MR)
    - Often multiple (esp in steatotic liver)
  • Polycystic Kidney Disease: Facts
    - Autosomal dominant with nearly a 100% penetrance
    - Defect on short arm of chromosome 16
    - Cysts also occur in liver (up to 80% of cases), and pancreas (up to 9% of cases)
    - Patients may also have an increased incidence of cerebral aneurysms
  • Nodular Regenerative Hyperplasia (NRH): CT Findings
    - Hypodense lesions that do not enhance
    - May be multiple
    - Often simulates metastatic disease
  • Nodular Regenerative Hyperplasia (NRH): Facts
    - Regenerative nodules surrounded by atrophic liver in the absence of fibrosis
    - Nodules range in size from several mm to several cm
    - Often seen in association with underlying diseases like lymphoproliferative disorders, autoimmune disorders, collagen vascular disease and Budd Chiari syndrome
  • Hepatic Adenoma: CT Findings
    - Well defined and may have a pseudocapsule in 25-30% of cases
    - May contain fat or calcification
    - Lesions under 4 cm enhance homogeneously and larger lesions have necrosis and have heterogeneous enhancement
  • Hepatic Adenoma: Facts
    - Usually in woman over 30 years of age but can occur in woman age 10 or so
    - Birth control pills are common in all cases in children
    - Occur in glycogen storage disease type I and III
    - Key findings are intratumoral hemorrhage or liver rupture
  • Focal Nodular Hyperplasia: CT Findings
    - Well circumscribed mass
    - Uniform enhancement on arterial phase imaging
    - Prominent feeding arteries seen
    - Becomes isodense on later phase images
  • Focal Nodular Hyperplasia: Facts
    - Uncommon in children and young adults
    - More common in females
    - May be incidental finding or present with a mass or abdominal pain
    - Central scar is classic in FNH
  • Mesenchymal Hamartoma: CT Findings
    - Complex cystic mass
    - Septa may be seen and enhance
    - Solid components may also be seen
  • Mesenchymal Hamartoma: Facts
    - Second most common benign liver mass
    - Age usually younger than 2 years of age, while all lesions are discovered by age 5 years
    - Usual presentation is abdominal distension
  • Infantile Hemangioendothelioma: CT Findings
    - Multifocal lesions are usually small
    - Large focal lesions often demonstrate findings related to central hemorrhage, necrosis, fibrosis, and calcification
    - Diffuse disease the liver is enlarged and replaced by multiple masses
  • Infantile Hemangioendothelioma: Clinical Presentation
    - High output congestive heart failure
    - Kasabach-Merritt syndrome of coagulopathy due to intratumoral platelet sequestration
    - Hypothyroidism
    - Memoperitoneum due to tumor rupture
  • Infantile Hemangioendothelioma: Facts
    - AKA infantile hepatic hemangioma
    - Vascular neoplasm
    - Most common benign hepatic tumor of infancy 90% are diagnosed in the first 6 months of life, and rare after age 1
    - Half the cases are solitary and half are multifocal
  • Benign Liver Tumors in the Pediatric Patient
    - Infantile hemangioendothelioma
    - Focal nodular hyperplasia (FNH)
    - Mesenchymal hamartoma
    - Nodular regenerative hyperplasia (NRH)
    - Hepatocellular adenoma
  • "Benign hepatic masses in children include tumors that are unique to children and others that are more common in adults. Knowledge of the pathologic spectrum of hepatic lesions in children and how their pathologic features are represented helps the radiologist direct proper evaluation and treatment of children with focal liver masses."

    Pediatric Liver Masses: Radiologic-Pathologic Correlation Part 1: Benign Tumors
    Chung EM et al
    RadioGraphics 2010; 30:801-826


  • "Hepatic adenomas occur more frequently and more often are multiple in patients with hepatic steatosis."

    Multiple Hepatic Adenomas Associated with Liver Steatosis at CT and MRI: A Case-Control Study
    Furlan A et al
    AJR 2008;191:1430-1435

  • Hepatic Hemangiomas: Clinical Syndromes
    - Klippel-Trenaunay-Weber syndrome
    - Osler-Rendu-Weber disease
    - Von Hippel-Lindau disease
  • Biliary Cystadenoma: CT Findings
    -May range for a few cm to 35 cm in size
    -Multiple septations are very common
    -Internal septa and mural nodularity may be seen
    -Cystadenomas may represent the premalignant form of cystadenocarcinoma
  • Focal Nodular Hyperplasia: CT Findings
    - Non contrast CT: isoattenuating or hyperattenuating
    - Arterial phase CT: hypervascular but homogeneous with large feeding artery
    - Venous phase CT: isodense to remaining liver
  • Hepatic Adenoma: CT Findings
    - Non contrast CT: hypodense or isodense
    - Arterial phase: moderate enhancement
    - Portal phase CT: lesions enhance similar to surrounding liver
    - Delayed phase CT: lesions enhance similar to surrounding liver
  • Hepatic Adenoma: CT Findings
    - Well defined mass that may contain hemorrhage, necrosis, fat and rarely calcification
    - Non contrast CT: hypodense or isodense
    - Arterial phase: moderate enhancement
    - Portal phase CT: lesions enhance similar to surrounding liver
    - Delayed phase CT: lesions enhance similar to surrounding liver
  • Hepatic Adenoma: Facts
    - Majority are solitary (80%)
    - Typically in female patients (90%)
    - Predisposing factors include
    ----Oral contraceptive use
    ----Anabolic steroid use
    ----Glycogen storage disease (type IA)


  • "Familiarity with both expected and unexpected imaging appearances of common benign hepatic tumors, less commonly encountered benign hepatic tumors, and iatrogenic abnormalities potentially masquerading as hepatic tumors allows the radiologist to achieve an informed differential diagnosis."

    Benign Hepatic tumors and Pseudotumors
    Anderson SW, Kruskal JB, Kane RA
    RadioGraphics 2009; 29:211-229

  • FNH: Key Differential Dx Points

    - Enhances to level of IVC, never aorta
    - Feeding vessel to center of lesion
    - Central scar which is often vascular on arterial phase but isodense on later phases
    - Lesion becomes isodense in late venous phase
  • "In noncirrhotic livers, relatively large size is a significant or trend-level predictor for benign tumors. Homogeneously hyperenchancing = 22 mm that fade to isoattenuation are benign; smaller masses may be malignant."

    Transient Homogeneously Enhancing Hepatic Masses: Can Size Predict Benignity
    Hughes-Cassidy F et al.
    AJR 2008; 190:300-307
  • "A mass diameter of = 22 mm had a 100% positive predictive value for benignity and excluded malignancy. By comparison masses = 21 mm were approximately equally likely to be benign or malignant."

    Transient Homogeneously Enhancing Hepatic Masses: Can Size Predict Benignity
    Hughes-Cassidy F et al.
    AJR 2008; 190:300-307
  • "Hepatic Adenomas are mildly hypervascular at contrast enhanced CT and MR imaging, and heterogeneous due to the presence of hemorrhage, necrosis, calcifications and fat."

    CT and MR Imaging Evaluation of Hepatic Adenoma
    Brancatelli G et al.
    J Comput Assist Tomogr 2006;30:745-750
  • Hepatic Adenomas: Facts

    - Associated with oral conreaceptive use and androgen steroid therapy
    - Increased incidence with type 1 glycogen storage disease, iron overload related to beta thalassemia, and diabetes mellitus
    - Can have spontaneous bleed in 10% of cases
  • "These features can help in the differentiation of this benign lesion from other hypervascular lesions without the need for additional imaging, biopsy, or surgery."

    Focal Nodular Hyperplasia: Lesion Evaluation Using 16-MDCT and 3D CT Angiography Kamel IR,Liapi E, Fishman EK AJR 2006 June;186(60:1587-1596
  • Hypervascular Liver Lesions: Nonneoplastic

    - Hepatic artery aneurysm and pseudoaneurysm
    - Arterioportal venous shunt or fistulae
    - Portosystemic shunt
    - Anomalous paraumbilical venous drainage to the left lobe of the liver
  • Hepatic Cysts: Facts

    - Water attenuation
    - Lack of enhancement on any phase of acquisition
    - Can be single or multiple
    - Polycystic liver disease will often accompany polycystic renal disease
  • Cystic Hepatic Lesions:Differential Diagnosis

    - Cyst
    - Biliary cystadenoma
    - Cystic metastases
    - Abscess (especially amebic)
    - Biloma
  • "Patients with FNH are more likely to have an associated hepatic hemangioma than are those with another type of hepatic mass."

    Prevalence of Hepatic Hemangioma in Patients with Focal Nodular Hyperplasia Vilgrain V et al. Radiology 2003; 229:75-79
  • Focal Nodular Hyperplasia

    - Benign hepatic neoplasm
    - 3-5% of general population
    - Usually an incidental finding in young woman
    - Hypervascular lesion with differential dx including hepatic adenoma, hemangioma, hepatoma and vascular metastases
  • Focal Nodular Hyperplasia

    - Multiple in up to 25% of cases
    - Fibrous scar more common in larger lesions (35% of lesions less than 3 cm, 65% of lesions greater than 3 cm)
    - Feeding vessel w/o neovascularity common on CTA in arterial phase
  • CTA Features of FNH

    - Enlarged feeding artery usually central in location
    - No neovascularity seen
    - Best seen with MIP imaging
  • "MDCT with advance image processing is a powerful tool that may be utilized to identifying the imaging features of FNH."

    Focal Nodular hyperplasia: Lesion Evaluation Using 16-MDCT and 3D CT Angiography Kamel IR, Liapi E, Fishman EK AJR 2006; 186:1587-1596..
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