# Renal Cell Carcinoma in a Patient With Crossed Renal Ectopia: A Case Report

## TL;DR

A rare case of crossed fused renal ectopia combined with renal cell carcinoma is reported and discussed.

## Contribution

This paper presents a rare case of crossed renal ectopia with primary renal cell carcinoma and discusses its management.

## Key findings

- A 59-year-old patient presented with crossed fused renal ectopia and primary renal cell carcinoma.
- Partial nephrectomy is uncommon in such cases due to the complex anatomy.
- The case is compared with existing literature to improve understanding and management of similar conditions.

## Abstract

Crossed fused renal ectopia (CFRE) is a rare congenital anomaly in which a kidney is located on the opposite side from where its ureter connects to the bladder, merging into the other kidney. It has been linked to other rare congenital malformations, including the VACTERL association (vertebral anomalies, anal atresia, cardiac anomalies, tracheoesophageal fistula, esophageal atresia, renal anomalies, and limb abnormalities), the MURCS association (müllerian ducts, renal, and cervicothoracic spine anomalies), increased incidence of infections, obstruction, cystic dysplasia, and urolithiasis. Although the literature has documented only a small number of cases wherein CFRE coincides with neoplasia, we present the case of a 59-year-old patient with a right ectopic kidney fused to the left one and simultaneous primary renal cell carcinoma. We aim to report and discuss this case and the treatment approach, comparing it with existing literature to enhance our understanding and management of similar occurrences, as partial nephrectomy is uncommon due to the challenging anatomy of these cases.