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GU: Female Pelvis/Endocrine

E2834. Atypical Uterine Leiomyomas: A Sheep in Wolf’s Clothing

Abadi S1,2,  Amnon A1,  Reiss A1,  Javitt M.1 1. Rambam Health Care Campus, Haifa, Israel; 2. Technion, Israel Institute of Technology, Haifa, Israel

Address correspondence to S. Abadi (s_abadi@rambam.health.gov.il)

Background Information: Uncomplicated common benign uterine leiomyomas (LMs) are easily recognized on imaging. However, with degeneration, a wide variety of imaging features with more ominous appearances may mimic gynecologic and other pelvic malignancies.

Educational Goals/Teaching Points: LMs are benign uterine smooth muscle tumors that are the most common solid pelvic masses in women. The typical presenting symptoms are vaginal bleeding or mass effect causing pain and discomfort. LMs are a significant public health problem estimated to cost billions of dollars annually. The identification of typical uncomplicated LMs without degeneration on pelvic US and MRI is straightforward. However, with degenerative changes the imagine features can be misleading. Knowing the anatomical variants, the pathophysiology of the different subtypes of degeneration and the various imaging modalities makes it possible to make the correct diagnosis.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques: In case of uncomplicated LMs, Ultrasound shows focal round hypoechoic solid uterine lesions, while MR depicts focal round low T2 signal lesions compared to myometrium, and dark signal on both DWI and ADC images. Degeneration of LMs can be cystic, hyaline, carneous, calcific, or mixed. The differential diagnosis of degenerated LMs and their differentiation from leiomyosarcomas and other gynecologic and pelvic malignancies can be very challenging. The spectrum of imaging findings in benign degenerated LMs is presented with emphasis on differential diagnosis and problem solving on US, CT, and MRI. Analysis of the location, morphology, bridging vessels, vascular supply and drainage, enhancement patterns, and relevant clinical history may lead to the correct diagnosis. Recent work on texture analysis holds promise for the reliable diagnosis of leiomyosarcomas and their differentiation from benign LMs using characteristics such as nodular border, foci of hemorrhage, dark T2 signal areas, central necrosis, and patient age. Among the cases we include in the presentation are suspected large ovarian cystadenoma from LM with cystic degeneration; presumed ovarian fibroma from broad ligament LM; presumed hemorrhagic cystic ovarian neoplasm from a pedunculated hemorrhagic subserosal LM; suspected endometrial malignancy from degenerated submucosal LM, later spontaneously vaginally extruded; and complex solid and cystic pelvic mass during pregnancy from hydropic degeneration of cervical LM.

Conclusion: Heightened awareness of diverse findings, distinguishing features, and clinical clues are essential for the correct diagnosis of benign atypical LMs.