# Synchronous Sigmoid Colon and Small Bowel Adenocarcinomas: A Rare Case of Dual Primary Malignancies Presenting With Acute Bowel Obstruction

## TL;DR

A rare case of two primary cancers in the colon and small bowel was successfully treated with surgery and targeted chemotherapy.

## Contribution

This case report documents a rare instance of synchronous colorectal and small bowel adenocarcinomas successfully managed with aggressive treatment.

## Key findings

- Synchronous tumors in the sigmoid colon and small bowel were identified with peritoneal metastases.
- Histopathology confirmed two distinct primary adenocarcinomas.
- KRAS mutation-guided chemotherapy contributed to a two-year disease-free outcome.

## Abstract

Synchronous colorectal and small bowel adenocarcinomas are exceptionally rare. This case report presents a 65-year-old male patient with acute bowel obstruction who underwent an emergency laparotomy. Intraoperative findings revealed synchronous sigmoid colon and small bowel tumors with peritoneal metastases. The patient underwent sigmoidectomy, small bowel resection, and metastasectomy. Histopathology confirmed two distinct primary adenocarcinomas. Postoperative management included KRAS mutation-guided chemotherapy. At the two-year follow-up, the patient remained disease-free. This case highlights the importance of thorough intraoperative exploration in emergency presentations and demonstrates the potential for favorable outcomes with aggressive multimodal treatment in synchronous gastrointestinal malignancies.