# Case Report: A rare case of mixed epithelial and stromal tumor of the kidney in an adolescent: imaging findings and literature review

## TL;DR

A rare kidney tumor in a 13-year-old girl is reported, highlighting MRI as a key tool for identifying its features in children.

## Contribution

The first detailed MRI and CT findings of a large pediatric MESTK case are presented.

## Key findings

- MRI showed adipose components and no diffusion restriction in the tumor.
- The tumor was the largest pediatric MESTK case reported to date.
- Radiologists should consider MESTK in children with large solid renal tumors without diffusion restriction.

## Abstract

Mixed epithelial and stromal tumor of the kidney (MESTK) is an unusual biphasic benign renal neoplasm. It predominantly occurs in perimenopausal women, with only eight cases reported in children. Owing to its rarity, only limited radiological information has been reported in the literature, in none of the previous pediatric cases were both CT and MRI findings of the tumor provided. Herein, we report a rare case of MESTK in a 13-year-old girl. This case was the largest observed in children to date. Findings from our report provide novel insights into the MRI features of a large pediatric MESTK and indicate the importance of MRI for observing adipose components and the absence of diffusion restriction within the tumor. Radiologists should consider the possibility of MESTK in children when they observe a large, solid renal tumor without diffusion restriction in children.