# Benign Enchondroma in a 40-Year-Old Female: Emphasizing the Importance of Early 18F-FES PET/CT Utilization

## TL;DR

A 40-year-old woman with breast cancer had a benign bone lesion detected, and early use of 18F-FES PET/CT helped avoid unnecessary procedures.

## Contribution

Highlights the clinical value of early 18F-FES PET/CT in breast cancer staging to reduce unnecessary interventions.

## Key findings

- A bone scan showed abnormal femur uptake, but MRI revealed a benign enchondroma.
- 18F-FES PET/CT ruled out estrogen receptor expression and metastatic disease.
- Biopsy confirmed the lesion was a benign enchondroma.

## Abstract

A 40-year-old female with estrogen receptor–positive breast cancer underwent an initial staging using a technetium-99m methylene diphosphonate (Tc-99m MDP) bone scan, which revealed abnormal uptake in the femur without a patient history of prior trauma or associated symptoms. Subsequently, an MRI confirmed the presence of a well-defined lesion in the upper left femur. To rule out metastatic disease, an 18F-fluoroestradiol (FES) PET/CT was performed, demonstrating no ER expression. Following the PET/CT, a biopsy confirmed the presence of an enchondroma. This case underscores the importance of early utilization of 18F-FES PET/CT in breast cancer staging to minimize unnecessary additional procedures/imaging.