Acoustic shadowing from uterine leiomyomas: sonographic-pathologic correlation.

PURPOSE

To investigate the origin of discrete shadowing from uterine leiomyomas at ultrasound (US) that does not progress from an echogenic origin.

MATERIALS AND METHODS

Seven hysterectomy specimens with leiomyomas were scanned in a water bath. With US guidance, 13 self-retaining needles were placed at the origin of shadows that did not (12 cases) or did (one case) arise from an echogenic focus. The localized tissues were inspected for gross pathologic features and microanatomic detail.

RESULTS

In the 12 cases, the shadow originated from transitional zones: the margins of the fibroid with adjacent myometrium (three needles), the edges of nodular whorls of smooth muscle (four needles), and the margin between smooth muscle bundles and hyalinized connective tissue (five needles). There was no evidence of calcification, hemorrhage, or necrosis. In the other case, microcalcifications were found.

CONCLUSION

Discrete shadowing not arising from echogenic foci resulted from the structural features of the leiomyomas and occurred at transitional boundaries between juxtaposed tissue types or at the curved margins of organized anatomic structures.