Uterine smooth muscle tumor of uncertain malignant potential

Abstract

Uterine smooth muscle tumors of unknown malignant potential (STUMPs) are neoplasms with intermediate characteristics between their malignant (leyomiosarcoma) and benign counterpart (leyomioma), and represent a diagnostic challenge for both the clinician and the pathologist. Clinical presentation of STUMP does not differ from that of ordinary leiomyoma, as signs and symptoms are related to mass-effect or lesion bleeding, and the imaging has a limited value in their identification. Hence preoperative distinction of STUMPs is almost impossible and generally the surgical approach is the same as for usual fibroids. The histological diagnosis of uterine smooth muscle tumors is based on three morphological criteria: atypia, necrosis and mitoses. STUMPs are referred as tumors with histopathological features that preclude an unequivocal diagnosis of leyomiosarcoma, but that do not fulfill the criteria for leiomyoma or its variants. Currently, no immunohistochemical marker nor molecular analysis is able to predict the recurrent disease. The absence of reliable clinical, pathological or molecular prognostic factors, make difficult standardization of management and follow up of patients. Current literature data recommend at least annual clinical surveillance, especially in patients that underwent conservative surgery, until ten years from diagnosis.