Hypoglycaemia has a very broad differential diagnosis. It is important to perform a thorough examination of the possible causes. Doege-Potter syndrome is a rare paraneoplastic syndrome that is associated with refractory hypoglycaemia and is caused by solitary fibrous tumours (SFTs). Diagnosis can be suspected based on imaging and clinical presentation, but the definitive diagnosis requires histologic confirmation. Most SFTs are located in the thorax. Therefore, imaging plays a major role in the diagnosis. CT scan should be performed when diaphragm elevation is seen on X-ray to exclude underlying masses and to make the differential diagnosis with diaphragm paralysis. Treatment of SFT is still not established, and no clear guidelines are available. In this case report, we describe the case of a 65-year-old woman who presented with refractory hypoglycaemia caused by a thoracic SFT.