ABSTRACT
Introduction · Leiomyomata and leiomyosarcoma
Mesenchymal tumors other than leiomyomata (leiomyomata) are uncommon; sarcomas of the uterus comprise only 3% of uterine malignan cies.1 Uterine sarcomas encompass leiomyosar coma (LMS), carcinosarcoma, and endometrial stromal sarcoma (ESS) according to traditional classification systems. The biphasic cellular pop ulation found in carcinosarcomas entered the sphere of interest of many researchers, who focused on whether this tumor originated from one (monoclonal theory) or two cell populations. A wide spectrum of methods has been elabo rated to answer this question. During the last 15 years, epidemiological, clinicopathological, immunohistological, in vitro, in vivo, and molec ular genetic research have found arguments to support the monoclonal nature of carcinosar coma that pointed towards an endometrial origin. As a result, recent textbooks classify carcinosarcomas as a subtype of endometrial cancer, rather than a uterine sarcoma.2 Based on these recent insights, the current chapter will only address benign (leiomyoma) and malignant (LMS and ESS) pure mesenchymal tumors, and we have opted to select themes from pathologi cal, genetic, molecular, and diagnostical view points, mainly based on their significance and importance.
