RadioGraphics 2008; 28:1931-1948
Najla Fasih, FRCR , Alampady K. Prasad Shanbhogue, MD, MBBS David B. Macdonald, MD , Margaret A. Fraser-Hill, MDCM, FRCPC Demetrios Papadatos, MD , Ania Z. Kielar, MD , Geoffrey P. Doherty, MD Cynthia Walsh, MD, FRCPC , Matthew Mclnnes, MD , MostafaAtri, MD
Uterine leiomyomas affect 20%-30% of women older than 35 years. Extrauterine leiomyomas are rarer, and they present a greater diagnos¬tic challenge: These histologically benign tumors, which originate from smooth muscle cells, usually arise in the genitourinary tract (in the vulva, ovaries, urethra, and urinary bladder) but may arise in nearly any anatomic site. In addition, unusual growth patterns may be seen, including benign metastasizing leiomyoma, disseminated peritoneal leiomyomatosis, intravenous leiomyomatosis, parasitic leiomyoma, and retroperitoneal growth. In the presence of such a pattern, a synchro¬nous uterine leiomyoma or a previous hysterectomy for removal of a primary uterine tumor may be indicative of the diagnosis. However, some extrauterine leiomyomas may mimic malignancies, and serious diagnostic errors may result. The most useful modalities for detecting extrauterine leiomyomas are ultrasonography, computed tomography, and magnetic resonance (MR) imaging. The superb contrast resolu¬tion and multiplanar capabilities of MR imaging make it particularly valuable for characterizing these tumors, which usually show low sig¬nal intensity similar to that of smooth muscle on T2-weighted images. The radiologist's recognition of this and other characteristic features may help steer the clinician toward timely, appropriate management and away from unnecessary, potentially harmful treatment.