Review Note
Last Update: 02/18/2024 05:30 AM
Current Deck: Part 2::1. Subsites::Gastrointestinal tract::Liver metastases
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GI | Liver mets | 2.1 | Differential diagnosis | List differential diagnoses for liver metastases and briefly describe their clinical and imaging characteristics
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- Prevalence
- Incidental hepatobiliary findings occur in ~6% of CT
- Differential diagnosis
- Benign lesions
- Hepatic haemangioma (aka cavernous haemangiomas)
- Epidemiology
- I: Most common benign liver lesions
- A: May be diagnosed at any age; most commonly diagnosed (80%) betewen 30-50yo
- S: More commo in women M:F 1:3
- Imaging appearance:
- Most often solitary but may be multiple
- Clinical features:
- Majority asymptomatic
- Excellent prognosis
- Focal nodular hyperplasia
- Pathology: Benign liver lesion composed of a proliferation of hyperplastic hepatocytes surrounding a central stellate scar
- Epidemiology:
- I: Prevalance 0.2-1.6% as incidental finding on CT or US
- S: More common in women
- Imaging appearance:
- Typically solitary
- Hepatocellular adenoma (aka hepatic adenoma)
- Pathology: Benign liver lesion that develops in an otherwise normal-appearing liver
- E:
- I: Uncommon
- S: More common in young women
- RFs:
- Estrogen-containing medications
- Glycogen storage disease
- Metabolic syndrome
- Imaging apperance: Solid, typically solitary lesion
- Regenerative nodules
- Develop in response to liver injury
- Comprised of a proliferation of hepatocytes and surrounding stroma
- Typically seen in the setting of cirrhosis
- Malignant lesions
- Hepatocellular carcinoma
- Primary liver tumour, develops in setitng of chronic liver disease (esp. cirrhosis of any cause, or chronic hepatitis B infection)
- Cholangiocarcinoma
- Arise from the epithelial cells of intra- and extra-hepatic bile ducts
- May be foudn incidentally during the early stage of disease
- RFs:
- Primary sclerosing cholangigtis
- Firbopolycystic liver disease (e.g. choledochal cysts)
- Hepatolithiasis
- Metastatic disease
- RFs: history of malignancy
- Imaging characteristics
- Size
- Most incidental lesions <1cm are benign; while some small lesions may be difficult to definitively characterise by imaging mehtods
- Most lesions >=1cm can be diagnosed either by further imaigng (e.g. MRI) and/or histology
- Marign - benign lesions typically have smooth margins
- Enhancement pattern on contrast-enhanced imaging - most lesions have characteristic enhancement features
- Hepatic haemangioma:
- Early phase: Peripehral nodular enhancement
- Late phase: Centripetal pattern or "filling in" duirng the late phase
- Lesion usually opacifies after a delay of >=3 minutes and remains isodense or hyperdense on delayed scans
- Hepatocellular adenoma
- Early phase: Well-demarcated leison with peripheral enhancement (reflects the large subcapsular feeding vessels)
- Portal venous phase: Centripetal flow
- Focal nodular hyperplasia
- Non-contrast: Hypo- or isodense with a central scar
- Arterial phase: Hyperdense
- Portal venous phase: Typically isodense, although the central scar may become hyperdense as contrast diffuses into the scar
- Hepatocellular carcinoma
- CT
- Arterial phase: Hypervascular relative to liver parenchyma
- Later phases: Washout of contrast
- MRI
- T1: low intensity
- T2: highintensity
- Intrahepatic cholangiocarcinoma
- CT
- Hypodense lesion with peripheral (rim) enhancement
- MRI
- T1: Hypointense
- T2: Hyperintense
- Dynamic images: Peripheral rim enhancement followed by progressive and concentric filling-in of the tumour with contrast material
- Liver metastases
- CT
- Colon, stomach, pancreas: Usually lower attenuation (i.e. are darker) in contrast to hte brighter surrounding liver parenchyma
- Hypervascular metastases (e.g. neuroendocrine tumour, RCC) appear as rapidly enhacning lesions visible on the arterial phase
- MRI
- T1: low signal
- T2: Moderately high signal
- Diagnostic approach for and incidental liver lesion
- Risk factors for HCC (Cirrhosis, chronic hepatitis B infection)
- Further tailored imaging for HCC
- History of malignancy
- Further evaluation depends on the primary malignancy
- Neither HCC risk factors or history of malignancy
- Imaging features of haemangioma: Typical features (homogenous, hyperechoic, well-delineated), size <3cm) -> no further imaging necessary
- Contrast enhanced multiphase cross-sectional imaging (e.g. MRI)
- If above insufficient to make diagnosis; options include:
- Obtain tissue for histology (biopsy or surgical resection)
- Monitor with surveillance imaging (individualised, but usually 6-12 months)
Further information, not for memorising (no card)
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