<prompt> Uterine leiomyoma is least likely to undergoeMalignant changeHyaline changeCalcificationRed degeneration  <response>: Refer 9e 1020 Leiomyomas are sharply circumscribed, discrete, round, firm, gray-white tumors varying in size from small, barely visible nodules to massive tumors that fill the pelvis. Except in rare instances, they are found within the myometrium of the corpus. Only infrequently do they involve the uterine ligaments, lower uterine segment, or cervix. They can occur within the myome- trium intramural, just beneath the endometrium submucosal or beneath the serosa subserosal Fig. 22-28A. Whatever their size, the characteristic whorled pattern of smooth muscle bundles on cut section usually makes these lesions readily identifiable. Large tumors may develop areas of yellow-brown to red softening. Leiomyomas are typically composed of bundles of smooth muscle cells that resemble the uninvolved myometrium 