Uterine leiomyomas: Histopathologic features, MR imaging findings, differential diagnosis, and treatment

Leiomyomas are the most common uterine neoplasm and are composed of smooth muscle with varying amounts of fibrous connective tissue. As leiomyomas enl arge, they may outgrow their blood supply, resulting in various types of de generation: hyaline or myxoid degeneration, calcification, cystic degenerat ion, and red degeneration. Leiomyomas are classified as submucosal, intramu ral, or subserosal; the latter may become pedunculated and simulate ovarian neoplasms. Although most leiomyomas are asymptomatic, patients may present with abnormal uterine bleeding, pressure on adjacent organs, pain, inferti lity, or a palpable abdominal-pelvic mass. Magnetic resonance (MR) imaging is the most accurate imf aging technique for detection and localization of leiomyomas. On T2-weighted images, nondegenerated leiomyomas appear as well -circumscribed scribed masses of decreased signal intensity; however, cellu lar leiomyomas can have relatively higher signal intensity on T2-weighted i mages and demonstrate enhancement on contrast material-enhanced images. Deg enerated leiomyomas have variable appearances on T2-weighted images and con trast-enhanced images. The differential diagnosis of leiomyomas includes ad enomyosis, solid adnexal mass, focal myometrial contraction, and uterine le iomyosarcoma. For patients with symptoms, medical or surgical treatment may be indicated. MR imaging also has a role in treatment of leiomyomas by ass isting in surgical planning and monitoring the response to medical therapy.