Which of the following is LEAST likely to occur in leiomyoma of uterus?

Mitotic activity in leiomyomas is rare and is a key point in their differentiation from leiomyosarcoma. The typical appearance of leiomyomas may change if normal muscle tissue is replaced with various degenerative substances following hemorrhage and necrosis. This process is collectively termed degeneration, and the replacement substances dictate the naming of these degenerative types. Forms include hyaline, calcific, cystic, myxoid, carneous or red, and fatty. These gross changes should be recognized as common variants. Ref: Hoffman B.L., Schorge J.O., Schaffer J.I., Halvorson L.M., Bradshaw K.D., Cunningham F.G., Calver L.E. (2012). Chapter 9. Pelvic Mass. In B.L. Hoffman, J.O. Schorge, J.I. Schaffer, L.M. Halvorson, K.D. Bradshaw, F.G. Cunningham, L.E. Calver (Eds), Williams Gynecology, 2e.