Ultrasound & CT of Renal Oncocytoma

In this radiology lecture, the ultrasound and CT appearance of renal oncocytoma is revealed.

Key teaching points include:

Oncocytomas are benign, solid tumors.
13% patients have multiple oncocytomas, and 1/3rd have concurrent renal cell carcinoma.
Central stellate nonenhancing scar only seen in 1/3rd of cases, and more commonly in larger tumors.
Spoke-wheel angiographic pattern may be present, best visualized on ultrasound using microvascular flow, AKA superb microvascular imaging.
Often not possible to differentiate from renal cell carcinoma (RCC) with imaging.
Both oncocytoma and RCC can have central scar and/or spoke-wheel angiographic pattern.
Kim et al.* found segmental enhancement inversion (corticomedullary phase/early excretory phase) characteristic for oncocytoma, but subsequent studies have shown inconsistent results.
When evaluating a renal mass, if only have postcontrast and 15-minute delayed phase images, mass deenhancement of 15 HU or more suggests a solid mass, whereas no change is more consistent with a hyperattenuating cyst.**

*Kim JI, Cho JY, Moon KC, et al. Segmental enhancement inversion at biphasic multidetector CT: Characteristic finding of small renal oncocytoma. Radiology 2009;252(2):441–448.

**Macari M, Bosniak MA. Delayed CT to evaluate renal masses incidentally discovered at contrast-enhanced CT: Demonstration of vascularity with deenhancement. Radiology 1999;213:674-680.

To learn more about the Samsung RS85 Prestige ultrasound system, please visit: https://www.bostonimaging.com/rs85-prestige-ultrasound-system-4

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