Extrauterine Endometrial Stromal Sarcoma Mimicking Colorectal Cancer With Metastases

Extrauterine endometrial stromal sarcoma (EESS) is extremely rare, especially with the colorectum involvement. We describe F-18-FDG PET/CT findings of EESS in the sigmoid colon and rectum in a 46-year-old woman who complained diarrhea. F-18-FDG PET/CT revealed multiple hypermetabolic lesions in the abdomen and pelvis, including the sigmoid colon and rectum. Therefore, colorectal cancer with metastases was initially suspected; however, ultimately low-grade EESS was pathologically confirmed. Widespread EESS with intestine involvement revealed by F-18-FDG PET/CT should be carefully distinguished from colorectal cancer with metastases.

Automated summary

This article describes a rare case of EESS involving the sigmoid colon and rectum. The F-18-FDG PET/CT scan revealed multiple hypermetabolic lesions in the abdomen and pelvis, initially suspected to be metastatic colorectal cancer. However, pathological confirmation confirmed low-grade EESS. Therefore, it is important to carefully differentiate between widespread EESS with intestine involvement and colorectal cancer with metastases.