# Supernumerary kidney incidentally detected on staging CT scan: A rare case report

## TL;DR

A rare case of a person having an extra kidney was found during a cancer scan, highlighting the importance of recognizing such anomalies for surgical planning.

## Contribution

This case report adds to the limited literature on supernumerary kidneys and emphasizes their clinical relevance.

## Key findings

- A 55-year-old male was found to have a supernumerary kidney during a staging CT scan.
- The extra kidney had its own blood supply and normal function but did not affect cancer treatment.
- The case highlights the need for awareness of such anomalies in surgical planning.

## Abstract

Supernumerary kidneys are rare congenital anomalies arising from abnormal renal development, with fewer than 100 cases documented in the literature. A 55-year-old male presented with chronic nonbloody diarrhea and was diagnosed with a locally advanced rectal tumor. A staging CT scan incidentally revealed a right-sided supernumerary kidney measuring 4.5 cm, alongside a larger right kidney (7.3 cm) and a normal left kidney (10.2 cm), with independent arterial supply and normal excretory function. While this finding did not impact the patient's oncological treatment plan, awareness of such anomalies is essential for surgical planning to avoid complications. This case underscores the importance of recognizing supernumerary kidneys to guide clinical decision-making in oncological and urological interventions.