adrenal metastases

Imaging
features of adrenal masses. Left adrenal metastasis in a 62-year-old woman with lung cancer. Unenhanced CT (a), portal (b), and late phase (c) images show a left adrenal mass (arrow) with attenuation value of 26 HU on unenhanced CT (a) and “absolute percentage washout” of 15%. Staging 18F-FDG PET/CT (d) performed 3 months later revealed a left adrenal lesion (arrow) with high metabolic activity (SUVmax 14 g/mL) and increased in size in comparison with CT images. After chemotherapy, restaging 18F-FDG-PET/CT (e) showed morpho-functional disease progression of the adrenal lesion (arrow) with signs of central necrosis (SUVmax 19 g/mL with central necrotic area of absence of 18F-FDG uptake). Images of 18F-FDG-PET/CT provided by database of Nuclear Medicine Service, Fondazione Istituto G. Giglio, Cefalù, Italy
insightsimaging.springeropen.com • CC-by-4.0
Imaging
features of adrenal masses. Left adrenal metastasis in a 58-year-old woman with breast cancer. Axial unenhanced CT (a), portal phase (b), T2-weighted fast spin echo (c), b800 s/mm2 diffusion-weighted image (d), ADC map (e), and coronal three-dimensional fat-suppressed T1-weighted gradient recalled echo image in portal phase after contrast injection (f) show a left adrenal mass (arrow). This lesion intra-lesional hemorrhage presenting as spontaneously hyperdense area on unenhanced CT (a), hypointense on T2-weighted (c), and no enhancement on CT (b) and MR (f) images after contrast injection. The peripheral solid component of the lesion shows also restricted pattern of diffusion (d, e)
insightsimaging.springeropen.com • CC-by-4.0
Radiopaedia • CC-by-nc-sa 3.0 • de

Adrenal metastases are the most common malignant lesions involving the adrenal gland. Metastases are usually bilateral but may also be unilateral. Unilateral involvement is more prevalent on the left side (ratio of 1.5:1).

Epidemiology

They are present at autopsy in up to 27% of patients with known malignant epithelial tumors.

Pathology

Primary sites

Many primary tumors can potentially metastasize to the adrenal glands, commonly:

Other reported primary tumors include:

Radiographic features

CT

Adrenal metastases can have a variable CT appearances . They usually demonstrate less than 50% washout.

In patients with renal cell carcinoma and hepatocellular carcinoma who undergo dedicated adrenal CT imaging for known adrenal lesions, the enhancement washout of adrenal metastases can be similar to that of lipid-poor adrenal adenomas. As hypervascular lesions, they commonly show intense enhancement on the portal venous phase, usually more than 120 HU, and thus can be easily identified.

MRI

Exact signal characteristics can vary depending on the type of tumor. In general, commonly described signal characteristics include:

  • T1: usually exhibit low signal intensity
  • T2:  often show high signal intensity
  • T1 C+ (Gd): usually has progressive enhancement after administration of contrast material

An important diagnostic feature is the lack of signal loss on out-of-phase images (in contradistinction to that seen with adrenal adenoma).

Practical points

  • on CT, metastases usually demonstrate less than 50% washout
  • if intense enhancement of more than 120 HU is identified in the portal venous phase, washout should be ignored, and a hypervascular lesion such as renal cell carcinoma or hepatocellular carcinoma metastasis should be considered as a primary
  • MRI: no signal loss on out-of-phase images
Siehe auch:
und weiter:
Assoziationen und Differentialdiagnosen zu Metastasen der Nebenniere:
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