Sonohysterographic Findings of Endometrial and Subendometrial Conditions

Sonohysterography has become the standard test in the evaluation of dysfunctional uterine and postmenopausal bleeding because it allows reliable differentiation between focal and diffuse endometrial and subendometrial lesions, with the most common being polyps and submucosal fibroids. An endometrial polyp usually appears as a well-defined, homogeneous, polypoid lesion that is isoechoic to the endometrium with preservation of the endometrial-myometrial interface. Atypical polyps have cystic components, multiplicity, a broad base, and hypoechogenicity or heterogeneity. Submucosal fibroids are usually broad-based, hypoechoic, well-defined, solid masses with shadowing and an overlying layer of echogenic endometrium that distorts the endometrial-myometrial interface. Atypical fibroids are pedunculated or have a multilobulated surface. The major advantage of sonohysterography is that it can accurately depict the percentage of the fibroid that projects into the endometrial cavity. Endometrial hyperplasia usually appears as diffuse thickening of the echogenic endometrial stripe without focal abnormality, but occasionally focal hyperplasia can be seen. Endometrial cancer is typically a diffuse process, but early cases can appear as a polypoid mass. Adhesions usually appear as mobile, thin, echogenic bands that bridge a normally distensible endometrial cavity, but occasionally thick, broad-based bands or complete obliteration of the endometrial cavity is seen. Although endometrial lesions have characteristic features, a wide range of appearances is possible, with significant overlap between entities. Radiologists should be familiar with the broad spectrum of findings that may be seen at sonohysterography in both benign and malignant processes to raise the appropriate level of concern and to direct the clinician toward the appropriate means of diagnostic biopsy or surgery.