A 63-year-old man with history of a pT2N0M0 Stage II Grade 3 clear cell renal cell carcinoma who had undergone a laparoscopic left radical nephrectomy 18 months ago is found to have a new right adrenal mass.
The mass measures 3 cm in diameter and demonstrates an attenuation of 25 HU on non-contrast computed tomography (CT) scan.
A CT 15-minute adrenal washout study is performed and demonstrates 65% absolute washout characteristics.
Submit your diagnosis to see full explanation.
Classically, adrenal masses that “washout,” or lose more than 40%-60% of contrast enhancement 15 minutes after the contrast bolus, are managed as adenomas, since the specificity of an adrenal washout study is extremely high.1-9
Recent data, however, reveal that RCC (and hepatocellular carcinoma) metastases can exhibit washout characteristics identical to lipid-poor adenomas.10 These new findings have important clinical implications.
Answer: Given washout characteristics, the lesion is not a metastasis
This case was prepared by Alexander Kutikov, MD, of Fox Chase Cancer Center in Philadelphia.
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- Kutikov A, Crispen PL, Uzzo RG. Pathophysiology, evaluation, and medical management of adrenal disorders. In: Campbell-Walsh Urology, 10th ed. Edited by Wein AJ, Kavoussi LR, Partin AW, et al. Philadelphia: Elsevier, p. in press, 2011
- Choi YA, Kim CK, Park BK, Kim B. Evaluation of adrenal metastases from renal cell carcinoma and hepatocellular carcinoma: use of delayed contrast-enhanced CT. Radiology 2013;266:514-520.