Introduction: Uterine sarcomas are rare and aggressive tumors. In some cases they can cause rupture of the uterus with or without clinical and radiological symptoms. Therefore, it is important to observe patients with clinical and/or radiological suspicion of sarcoma, even when there are no clinical manifestations. Case report: A71-year old woman, who was under the authors' observation for pain in the right iliac fossa. The US and the CT scan showed an abdominal-pelvic mass.Laboratory tests showed a slight but progressive reduction of haemoglobin, which could not be explained by the clinical symptoms and by the results of the imaging tests. During the surgical intervention, a small amount of peritoneal fluid, an increased uterine volume, and a subverted anatomy were observed A haematoma was found in the uterus and this could explain the progressive reduction of haemoglobin and the very low presence of peritoneal effusion. Conclusion: The rupture of the uterus could not have been suspected as the patient did not have any type of symptoms, except for the slow and progressive reduction in the haemoglobin value. Therefore, it is important to observe patients with clinical and/or radiological suspicion of sarcoma, even when there are no clinical manifestations.