Uterine smooth muscle tumor of uncertain malignant potential: A review of current knowledge.

Uterine smooth muscle tumor of uncertain malignant potential is a subtype of uterine smooth muscle neoplasms. It is characterized by distinct pathologic findings with morphologic features intermediate between those of benign leiomyoma and malignant leiomyosarcoma. Clinically, STUMP is rare and its clinical picture is comparable to that of leiomyoma, with diagnosis typically being made postoperatively. Most patients with STUMP are uneventful after tumor resection. However, a small portion of patients may experience recurrence that may even lead to mortality. Given the uncommon occurrence of STUMP and the low frequency of malignant potential, currently there is still no standard guideline in treating patients with this disease and this can be challenging for physicians. Moreover, because cases are rarely available for study, investigating this tumor is difficult. Thus, matters such as the pathologic diagnostic criteria, strategy of clinical management, identification of prognostic factors, and the pathogenesis of this disease remain to be clarified. We collected and analyzed recently published case series studies of STUMP to obtain up-to-date clinical information. The current status of research in various basic and clinical aspects of this tumor was also reviewed.