myxoid degeneration of a leiomyoma

Myxoid degeneration of leiomyoma is one of the rarer types of degeneration that can occur in a uterine leiomyoma. This term is related but not identical to the term myxoid uterine leiomyoma.

Epidemiology

While this type of degeneration is generally considered rare, the highest prevalence for this type of degeneration has been reported as up to 50% of all degenerations of leiomyomas .

Pathology

Fibroids (i.e. uterine leiomyomas) that have undergone myxoid degeneration are filled with a gelatinous material and can be difficult to differentiate from cystic degeneration; however, they typically appear as more complex cystic masses. They appear hypocellular with a myxoid matrix .

Radiographic features

MRI

On pelvic MRI, the myxoid material usually demonstrates :

  • T1: low signal intensity 
  • T2: usually high signal intensity  with a peripheral low signal intensity
  • T1 C+ (Gd): there is minimal or no enhancement

The above signal changes are of intralesional change  on a background of low T2 signal of non-myxoid components.

Differential diagnosis

Certain malignant uterine tumors also show myxoid degeneration, e.g.leiomyosarcoma