# CT-imaging features of renal epithelioid angiomyolipoma

## TL;DR

This study describes the CT imaging features of a new type of kidney tumor called epithelioid angiomyolipoma to help with its recognition and understanding.

## Contribution

The paper provides a detailed characterization of CT imaging features specific to renal epithelioid angiomyolipomas.

## Key findings

- Most E-AMLs showed hyper-attenuation on precontrast CT with or without fat.
- A rapid wash-in to slow wash-out enhancement pattern was observed in 91% of cases.
- Contrast-enhanced CT features were markedly heterogeneous in 73% of the tumors.

## Abstract

The aim of this study was to describe the computed tomography (CT)-imaging features of renal epithelioid angiomyolipomas (E-AMLs) to understand and recognize this new category of renal tumors.

Institutional review board approval was obtained for this retrospective study. Clinical data and preoperative CT images of 11 cases of E-AML were retrospectively analyzed. All patients had unenhanced and tri-phase dynamic enhanced CT examination. CT-imaging features including tumor size, existence of fat and calcification, enhancement degree, enhancement pattern, and enhancement heterogeneity were evaluated.

The patients were ten women and one man. The size of tumor ranged from 1.8 to 10.3 cm. All of them had distinct edges; one had a lobulated appearance, ten had bulging contour of the involved kidney, and four lesions had intratumoral fat. Eight of the E-AMLs demonstrated hyper-attenuation, two as iso-attenuation, and one as hypo-attenuation compared with renal parenchyma on unenhanced CT images. Contrast-enhanced CT features were markedly heterogeneous in eight cases (73 %). The predominant enhancement pattern was rapid wash-in to slow wash-out (91 %).

The radiological appearance of most E-AMLs has a tendency to be hyper-attenuated on precontrast CT with or without fat component and demonstrates a rapid wash-in to slow wash-out dynamic enhancement pattern.