Cystic hepatic metastases
Cystic hepatic metastases are included in the differential for new cystic liver lesions. The internal cystic component may represent necrosis as the tumor outgrows its hepatic blood supply, or it may represent a mucinous component, similar to the primary tumor.
The liver and lungs are the most common sites of metastatic disease, and cystic hepatic metastases may arise from any number of primary tumors, but classically hepatic metastases arise from organs that have the opportunity of seeding the liver with metastases via the portal vein, including the gastrointestinal tract (stomach, small bowel, colon) and the pancreas.
The appearance of the metastases will vary depending on the primary. Multiplicity is a classic feature of hepatic metastases.
Target lesions and hyperechoic lesions are more common appearances for hepatic metastases than cystic lesions:
- centrally hypoechoic
- may have thick septations
- may show a hypoechoic halo, corresponding with proliferating metastatic cells or compressed hepatic parenchyma
- may demonstrate increased vascularity on color Doppler imaging
- lesion is centrally hypoattenuating relative to liver, unless complicated by internal hemorrhage
- irregularly thickened and enhancing wall
- irregularly thickened wall
- mild-moderate T2 hyperintensity
- metastases from mucinous tumors may approach the T2 signal intensity of hemangioma (although the enhancement is different)
T1 + C (extracellular):
- early rim enhancement with washout is characteristic, reflecting peripheral angiogenesis
- cystic mets may be predominantly hypovascular
- T1 + C (Eovist): no retention of contrast on the delayed sequence
Cystic hepatic metastases are part of the differential of cystic liver lesions. There is an overlap in imaging appearance with hepatic abscess. Classically, hepatic metastases are favored if there are multiple lesions (~98% of cases).
A cystic hepatic metastasis may arise from any source, but consideration of primary lesions should include:
- colon cancer
- ovarian cystadenocarcinoma
- squamous cell lung cancer
- gastrointestinal stromal tumor (GIST)
- pancreatic mucinous cystadenocarcinoma
- pancreatic neuroendocrine tumor: a metastasis with a fluid-fluid level on MRI is characteristic of a neuroendocrine tumor metastasis 4
- a large metastasis from any origin that has outgrown its blood supply
Cystic hepatic metastases are usually easily differentiated from hepatic cysts, since cystic metastases are usually much less well-marginated.
If considering placing a percutaneous drain into a presumed hepatic abscess, biopsy is mandatory since placing a drain in a cystic hepatic metastasis is contraindicated.
- 1. Middleton WD, Kurtz AB. Ultrasound. Mosby. (2004) ISBN:0323017029. Read it at Google Books - Find it at Amazon
- 2. Dalrymple NC, Leyendecker JR, Oliphant M. Problem Solving in Abdominal Imaging with CD-ROM. Mosby. ISBN:0323043534. Read it at Google Books - Find it at Amazon
- 3. Roth CG. Fundamentals of Body MRI: Expert Consult- Online and Print, 1e. Saunders. ISBN:141605183X. Read it at Google Books - Find it at Amazon
- 4. Sommer WH, Zech CJ, Bamberg F et-al. Fluid-fluid level in hepatic metastases: a characteristic sign of metastases of neuroendocrine origin. Eur J Radiol. 2012;81 (9): 2127-32. doi:10.1016/j.ejrad.2011.09.012 - Pubmed citation
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