This short course will provide a comprehensive overview of diagnostically challenging mesenchymal neoplasms occurring in the female genital tract, targeting residents, fellows and general pathologists. We intend to accomplish this goal by organizing the course in a case-study format, arranged by site (vulva, cervix, uterine corpus, ovary/peritoneum), discussing the most common mesenchymal neoplasms. Several uncommon cases will also be presented emphasizing helpful tips for categorization of tumors in the differential diagnosis. We also propose a series of short, structured discussions among course directors following each case presentation with time for questions after each case. The discussions will focus on each presenter’s practical approach to differential diagnosis, use of immunohistochemistry, assessment of prognostic indicators and diagnostic reporting. At the conclusion of the course, participants should be able to 1) formulate a differential diagnosis and understand pitfalls in diagnosis; 2) accurately diagnose gynecologic mesenchymal tumors using routine histologic, immunohistochemical and clinical data; 3) be familiar with the prognostic and therapeutic implications of their diagnoses; 4) use information presented in the course to communicate effectively with gynecologists for the benefit of their patients. A glass slide from each case discussed will be available for advance mailing. A detailed handout will be distributed at the course and a CD-ROM will be mailed after the course. (New Course)