Pleural fibroma or solitary fibrous tumor of the pleura (SFTP) is a rare tumor generally discovered fortuitously or in patients with non-specific respiratory symptoms, more rarely with hypoglycemia. We report the case of a 51-year-old man with a history of smoking (30 pack-years) and no other disease history whose chest x-ray revealed an enormous opacity occupying the lower two-thirds of the left hemithorax. This radiological anomaly had led to episodes of lipothymia three months earlier together with mental confusion in the morning as well as an episode of hypoglycemia (0.48 g/l) which rapidly resolved after administration of hypertonic dextrose. Ultrasonography and chest scan were performed later and confirmed the tissular nature of the opacity which was well limited with a left base. Minimally abundant homolateral pleural effusion was also noted. The diagnosis of SFTP revealed by hypoglycyemia was the most probably diagnosis. Emergency thoracotomy enabled removal of a hard tumor weighing 2115 g. Histology confirmed the diagnosis of benign SFTP. Hypoglycemia in the context of SFTP would be related to tumor secretion of insulin-like proteins. Complete emergency resection is required to avoid the risk of life-threatening hypoglycemia.