A Retroperitoneal Leiomyosarcoma Presenting as an Adrenal Incidentaloma in a Subject on Warfarin

Table 1

Adrenal imaging modalities and their utility.

Scan type	Diagnostic characteristics	Comments
Contrast enhanced; ultrasound	Arterial enhancement and rapid washout seen in nonadenomatous lesions	Not commonly used
Unenhanced CT scan	(a) Presence of macroscopic fat seen in myelolipoma; (b) Attenuation of less than 10 Hounsfield units (HU) seen in benign adrenal adenomas	Commonly used scan mode but 30–40% benign lesions are lipid poor
Multiphase CT	(a) Rapid washout, benign lesions; (b) Slower washout, malignant lesions	Useful when unenhanced CT is equivocal
MRI	Chemical shift imaging is helpful in differentiating between lipid poor adenomas and malignant adrenal lesions	Helpful when CT is contraindicated or washout values are equivocal
Positron emission tomography (PET) and PET-CT	Differentiate benign from malignant lesions with high sensitivity and specificity	Combine HU measurement with functional activity