1 3 Arch Gynecol Obstet DOI 10.1007/s00404-014-3311-8 GYNECOLOGIC ONCOLOGY Undifferentiated uterine sarcoma: a rare, not well known and aggressive disease: report of 13 cases Iván Ríos · Ángeles Rovirosa · Javier Morales · Blanca Gonzalez-Farre · Meritxell Arenas · Jaume Ordi · Jaume Pahisa · Albert Biete Received: 10 March 2014 / Accepted: 2 June 2014 © Springer-Verlag Berlin Heidelberg 2014 relapse. The median OS was 16 months, being 17 months for stage I and 9 for the remainder. Conclusions Poor outcome of UUS was associated with a high incidence of DM. Stage I had the best outcome. Radiotherapy seems to have benefited patients, with 100 % of local control and 50 % of long-term survivors. The high incidence of metastasis suggests the need for more accurate initial assessment. Keywords Undifferentiated uterine sarcoma · Radiotherapy treatment and uterine sarcoma · High grade uterine sarcoma Introduction Uterine sarcomas are rare tumors that affect 3–7/10,000 women in the United States and constitute 3–7 % of uter- ine neoplasms [1]. Characteristically, they are a heteroge- neous pathologic group of neoplasms, with an aggressive behavior and worse prognosis than endometrial carcinoma [2]. Following the 2003 World Health Organization (WHO) classification there are four main types of uterine sarcomas: leimyosarcoma, endometrial stromal sarcoma (ESS), aden- osarcoma, and undifferentiated sarcoma, each having a dif- ferent outcome and management [3]. Undifferentiated uterine sarcomas (UUS) are rare and aggressive uterine neoplasms. Historically, many tumors currently referred to as UUS were classified as high-grade ESS. A few small case series have shown that UUS behave more aggressively than the more widely described low- grade ESS [4]. The UUS have now been classified accord- ing to the last edition of the WHO, although it is still con- troversial whether high-grade ESS are actually UUS [3–6]. Based on the few reports published to date we know that Abstract Purpose Undifferentiated uterine sarcomas (UUS) are rare and aggressive tumor with scarce data on the outcome and best treatment. We aimed to describe the behavior among patients with UUS at our institution. Materials and methods Thirteen patients with UUS treated in our centre from 1979 to 2010 were analyzed. Statistics: descriptive analysis for frequencies and Kaplan– Meier actuarial method for overall survival (OS). Results Patients mean age was 66 years. Three had FIGO 2009 stage IA, five IB, two IIB, and three IVB. Ten patients underwent surgery and eight received postoperative radio- therapy. Three patients received adjuvant chemotherapy. The median follow-up was 16 months (2–276 months). Stage I patients developed two local relapses and three distant metastases (DM). DM was also observed in stage II patients and in 61.5 % of the entire series. Fifty percent of patients receiving radiotherapy remain alive without I. Ríos (*) · Á. Rovirosa · J. Morales · A. Biete Radiation Oncology Department, Hospital clinic, Universitat de Barcelona, C/villarroel n° 170, 08036 Barcelona, Spain e-mail: girios@clinic.ub.es I. Ríos · Á. Rovirosa · J. Morales · B. Gonzalez-Farre · J. Ordi · J. Pahisa · A. Biete Gynaecological Cancer Unit, Hospital Clínic, Universitat de Barcelona, Barcelona, Spain B. Gonzalez-Farre · J. Ordi Department of Pathology, CRESIB (Centre de Recerca en Salut Internacional de Barcelona), Hospital Clínic, Universitat de Barcelona, Barcelona, Spain M. Arenas Radiation Oncology Department, Hospital Sant Joan de Reus, Universitat Rovira i Virgili, Tarragona, Spain