Case Report Uterine gastrointestinal stromal tumour (GIST) Chantal B.M. Wingen a, T , Patrick A.A. Pauwels b , Maria Debiec-Rychter c , Wim G. van Gemert d , M. Caroline Vos a a Department of Obstetrics and Gynaecology, University Hospital Maastricht, P. Debeyelaan 25, 6229 HX Maastricht, The Netherlands b Department of Pathology, University Hospital Maastricht, The Netherlands c Center for Human Genetics, Catholic University Leuven, Belgium d Department of Surgery, University Hospital Maastricht, The Netherlands Received 4 December 2004 Available online 24 March 2005 Abstract Background. Gastrointestinal stromal tumours (GIST) are mesenchymal tumours which mostly arise in the gastrointestinal tract showing positive CD117 immunohistochemical staining. In recent years, other locations such as the mesentery and the retroperitoneum have been reported. Case. A 77-year-old woman presented with a pelvic mass, raising the suspicion of an ovarian or a uterine tumour. During laparotomy, a ruptured process arising from the uterus was seen and removed. Histologic features, immunophenotype and genotype of the tumour supported the diagnosis of a GIST. Conclusions. To the best of our knowledge, this is the first case of a primary GIST presenting as a uterine mass. Because of recent advances in GIST-therapy, making a correct diagnosis has major clinical implications. D 2005 Elsevier Inc. All rights reserved. Keywords: Gastrointestinal stromal tumour; GIST; CD 117; Uterus; Gain of function mutation(s) Introduction For a long time, a large group of mesenchymal tumours arising in the GI-tract have been classified as smooth muscle tumours (leimyomas or leiomyosarcomas) or neural tumours (schwannomas) [1,2]. In the 1980s, Mazur and Clark classified these tumours as stromal tumours because they lack the immunophenotypic features of smooth muscle or neural differentiation [2]. It was not until the late 1990s that an anti-c-kit immunohistochemical staining (CD117) was introduced as a sensitive–and in the proper context–specific marker for GIST. CD117 is considered as the gold standard for diagnosing GIST [1–6], although a very small subgroup of CD117 negative GISTs exist [7]. In 1998, Hirota et al. added much to our understanding of the pathogenesis of these tumours by describing an activating c-kit mutation in a series of GIST [2–5]. Nowadays, it is accepted that all GISTs have malignant potential and long-term follow-up is mandatory [2,4,5]. We present the first case of a large primary gastrointestinal stromal tumour presenting as a uterine mass in a 77-year-old female. Case report In December 2003, a 77-year-old multiparous woman was admitted to the department of internal medicine of our hospital with severe ferriprive anaemia [Hb: 2.9 mmol/l (4.7 g/dl)] and a deep vein thrombosis of the left leg. She was known with a compromised cardiovascular condition. She also had a diagnosis of breast carcinoma (T4N0M0) in 1992. Until now, no metastasis or recurrent disease had occurred. Ultrasound examination and CT scan of the abdomen revealed a pelvic mass (12.9 Â 8.9 cm), with a hypodens 0090-8258/$ - see front matter D 2005 Elsevier Inc. All rights reserved. doi:10.1016/j.ygyno.2005.01.053 T Corresponding author. Fax: +31 495 563086. E-mail address: chantal@wingen.nl (C.B.M. Wingen). Gynecologic Oncology 97 (2005) 970 – 972 www.elsevier.com/locate/ygyno