myxoid uterine leiomyoma

Myxoid uterine leiomyomas are a relatively rare pathological subtype of uterine leiomyomas.

Terminology

They are not to be confused with myxoid degeneration of a uterine leiomyoma which is a different entity.

Pathology

Myxoid leiomyomas contain abundant myxoid material between smooth muscle cells. The lesions are soft and translucent but solid. Large lesions may be clinically malignant even if they do not meet standard criteria for the diagnosis of sarcoma. In these lesions, smooth muscle cells are so widely separated by an abundant myxoid material that mitotic count and cellularity cannot be assessed precisely .

Radiographic features

MRI

Signal characteristics of the myxoid portion include:

  • T1: geographic and variable signal dependent on protein content
  • T2: high signal intensity 
  • T1 C+ (Gd)
    • enhances well except for small foci of mucinous lakes or clefts
    • delayed and prolonged enhancement is seen due to the presence of a myxoid stroma

Differential diagnosis