Cellular Leiomyoma of Uterus

Cellular leiomyomas are significantly more cellular than the normal myometrium but lack nuclear atypia, tumor cell necrosis or increased mitotic activity (mitotic rate is usually less than 4/10 HPF). The cells are small and round to spindle shaped. The natural history is the same as typical leiomyomas. Cytogenetically, cellular leiomyoma has been found to be accompanied by loss of almost the entire short arm of chromosome 1.