Submucosal leiomyomas of the uterus refer to a subtype of uterine leiomyoma that primarily projects into the endometrial cavity. They are least common albeit the most symptomatic type of leiomyoma.
Submucosal leiomyomas can be a common source of abnormal uterine bleeding and may also present with reproductive dysfunction, including recurrent miscarriages, infertility, premature labor, and fetal malpresentation. Submucosal leiomyomas can grow rapidly in pregnancy.
More common in premenopausal women, they are also a recognized cause of infertility.
It is typically seen as a subendometrial mass indenting and distorting the endometrium. Please, refer to the main article on uterine leiomyomas for a detailed discussion on leiomyomas imaging features.
On ultrasound, submucosal fibroids are typically seen as broad-based, hypoechoic, well-defined, solid masses with shadowing. Submucosal fibroids typically have an overlying layer of the echogenic endometrium, which helps confirm their subendometrial location and helps distinguish them from endometrial polyps. Also, as opposed to polyps, submucosal fibroids often distort the interface between the endometrium and myometrium and show acoustic attenuation.
When internal vessels are seen, a submucosal fibroid will typically have multiple feeding vessels, as opposed to the single vascular pedicle for an endometrial polyp .
General imaging differential considerations include: