MR Imaging of Adrenal Lesions

Aoife Kilcoyne, MB BCh BAO, FFR, RCSI; Shaunagh McDermott, MB BCh BAO, FFR, RCSI; Michael A. Blake, MB BCh BAO, MRCPI, FRCR, FFR, RCSI

Disclosures

Appl Radiol. 2017;46(4) 

In This Article

Malignant Adrenal Lesions: Adrenocortical Carcinoma, Metastases

Adrenocortical Carcinoma

Adrenocortical carcinoma (ACC) is a rare, malignant tumor of the adrenal gland. They are typically large at presentation and may have metastasized at the time of diagnosis.[32] ACCs are generally heterogeneous with areas of high signal intensity on T1-weighted and T2-weighted sequences, representing blood products and areas of necrosis within these lesions (Figure 6). Following administration of gadolinium, the viable portion of the tumor will enhance. Because this neoplasm originates from the adrenal cortex, it may contain foci of intracytoplasmic lipid, resulting in loss of signal intensity on OOP images, similar to an adenoma.[48] Although in most cases, it is not difficult to differentiate between an adenoma and an ACC, one should exercise caution in attempting to distinguish between a small ACC and an adenoma.

Figure 6.

Left adrenocortical carcinoma. Axial T1-weighted images pre- (A) and post-intravenous (B) contrast. The lesion demonstrates avid, heterogeneous enhancement post contrast.

Metastases

Metastases are the most common malignant lesions involving the adrenal gland.[42] Adrenal metastases are found in up to 27% of patients with malignant epithelial tumors at autopsy.[8] Metastases are usually bilateral but may also be unilateral. They usually demonstrate low signal intensity on T1-weighted images and relatively high signal intensity on T2 with progressive enhancement following administration of contrast material (Figure 7). The most important imaging feature is lack of signal drop-off on the OOP images, distinguishing this tumor from a lipid-rich adrenal adenoma.

Figure 7.

Right adrenal metastasis from lung adenocarcinoma. Axial and coronal T2-weighted images (A,B) demonstrate heterogeneous signal intensity. The lesion has internal septations and enhances (C, precontrast, D, postcontrast) following administration of intravenous contrast.

Lymphoma

Primary adrenal lymphoma is rare. Singh et al reported four cases from a series of 241 patients with non-Hodgkins lymphoma (NHL).[49] Secondary adrenal involvement is typically seen with NHL.[33] The MRI characteristics are nonspecific. Typically, the T1 signal intensity is lower than that of liver and the T2 signal is heterogenously hyperintense. They typically demonstrate only mild to moderate homogeneous (or mildy heterogeneous) enhancement after gadolinium.[50]

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