Representative histologic fields of several of the most common diagnoses reviewed during this study.Leiomyoma (case previously published) [6] is characterized by smooth muscle cells without atypia, mitoses, or necrosis. In contrast, atypical leiomyoma (case #7) shows atypia, but rare mitoses (up to 2 mitoses per 10 high power fields). Smooth muscle tumor of uncertain malignant potential (STUMP, case #11) is characterized by a higher rate of mitoses (3 to 8 mitoses per 10 high power fields) and more frequent atypia. Leiomyosarcoma (LMS, case #15) shows significant mitotic activity (over 10 mitoses per 10 high power fields), prominent atypia, and tumor necrosis.Peritoneal dissemination complicating morcellation of uterine mesenchymal neoplasms. Seidman MA, Oduyebo T, Muto MG, Crum CP, Nucci MR, Quade BJ - PloS one (2012). Not Altered. CC.