MRI-based pictorial review of the FIGO classification system for uterine fibroids

Uterine fibroids are the most common gynecologic neoplasm and contribute to significant morbidity, particularly when submucosal in location or large enough to cause bulk symptoms. Correctly classifying fibroids is essential for treatment planning and prevention of complications. Ultrasound is the first-line imaging modality for characterizing uterine fibroids. However, MRI allows for high-resolution, multiplanar visualization of leiomyomata that affords a more accurate assessment than ultrasound, particularly when fibroids are numerous. The FIGO system was developed in order to more uniformly and consistently describe and classify uterine fibroids. In this article, we review the MRI appearance of each of the FIGO classification types, detailing key features to report. Additionally, we present a proposed template for structured reporting of uterine fibroids based on the FIGO classification system.