Borderline smooth muscle tumors of the uterus.

At present, decision regarding where to place a uterine smooth muscle tumor that deviates from the most obvious leiomyoma and leiomyosarcoma groups still depends on time-honored conventional criteria. The focus of categorization should be the clinical outcome and not nosology. To improve accuracy in predicting clinical behavior, a multivariate approach is needed. This involves combining background clinical information, intraoperative and gross findings,multiple relevant morphologic criteria, and immunohistochemical studies. The authors believe that in future, as the number of cases with intermediate clinical outcome and morphologic features increases, and as molecular markers of prognosis are studied, managing these tumors will become more objective.