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Myometrial inhomogeneity

      Myometrial inhomogeneity can be attributed most commonly to adenomyosis and fibroids. I will discuss the clinical, sonographic, and pathologic features of these entities with numerous examples showing pathological-sonographic correlation. It is critical to begin by obtaining pertinent clinical information as well as performing a “physical examination” with the vaginal probe. The major causes of myometrial inhomogeneity are fibroids and adenomyosis. Fibroids are over-diagnosed, and adenomyosis is seriously under-diagnosed. Ultrasound should be the diagnostic method of choice because you can actually “palpate” the uterus during the study and define a fibroid mass or elicit the uterine tenderness of adenomyosis. MRI will not be discussed but also has been shown to be of value. Fibroids are well-defined masses and not the diffuse inhomogeneity that it so often ascribed to them. Both conditions may present with menorrhagia, but pain is a hallmark of adenomyosis and not of fibroids. Myometrial cysts are a common finding in adenomyosis. They are usually small (3 mm) and are in thesub-endometrial region of the myometrium. They are usually associated with focal uterine tenderness and likely represent distended ectopic endometrial glands. Cysts may come and go or fill with blood during menses. Occasionally, they will grow to several cm in diameter. In the past few years, women have expressed greater desire in having uterine-sparing procedures. This has led to the development of medical and minimally invasive alternative therapies to treat fibroids and adenomyosis. The principle characteristics and differentiating features are:
      Tabled 1
      FibroidsAdenomyosis
      Often in nulliparous womenUsually multiparous
      Distinct massIll-defined, no mass
      Hypoechoic peripheryAsymmetric myometrial thickening
      Hypo, iso, or hyperechoicMixed echogenicity
      Cysts are rareCysts are small and common
      Peripheral vesselsCentral vessels
      Diffuse shadowingStreaky shadows
      NontenderTender on palpation
      Calcify lateDo not calcify