Lipomatous uterine masses: potential to mimic ovarian dermoids on endovaginal sonography

Lipomatous uterine masses are uncommon hyperechoic pelvic neoplasms composed partly of adipose tissue. Because of the high level of echogenicity, these uterine masses can produce produce a sonographic appearance strikingly similar to the "dermoid plug" that is considered characteristic of benign cystic teratomas. The key to distinguishing the two tumors is to ascertain the parent organ: the lipomatous uterine mass should clearly originate from the myometrium. In our experience, however, the origin of some echogenic pelvic masses can be difficult to determine, particularly from the endovaginal perspective. This report describes the transabdominal and endovaginal ultrasonographic findings in three patients with lipomatous uterine masses for whom the endovaginal perspective alone, without supplemental transabdominal views, would have resulted in misdiagnosis.