# Unexpected Metastasis of Primary Colonic Adenocarcinoma: A Case Report and Literature Review

## TL;DR

This case report describes a rare instance of colonic cancer spreading to the bladder and reviews related literature.

## Contribution

The novelty lies in documenting an extremely rare bladder metastasis from colonic adenocarcinoma and discussing its unique characteristics.

## Key findings

- Bladder metastasis from colonic adenocarcinoma is an extremely rare occurrence.
- The case highlights the importance of considering unusual metastatic sites in cancer follow-up.
- Cystoscopy and biopsy confirmed the metastasis in the patient undergoing adjuvant chemotherapy.

## Abstract

Colorectal cancer is a common cancer worldwide. The major sites of colorectal cancer metastasis are the liver, lungs, peritoneum, lymph nodes, and bones. However, secondary localization in the bladder is extremely rare. Herein, we present the case of a 36-year-old patient who underwent surgery for colonic adenocarcinoma. Subsequently, the patient presented total hematuria during adjuvant chemotherapy. Cystoscopy and biopsy identified a bladder metastasis. In our discussion, we aim to delve into the distinct characteristics of bladder metastases originating from digestive neoplasms.