The synchronous occurrence of gastrointestinal stromal tumour (GIST) in the stomach and early gastric cancer is uncommon, with only a few previous reports. In particular, the collision of GIST and early gastric cancer in a patient with idiopathic thrombocytopenic purpura (ITP) has never been reported. We present the case of a 78-year-old male patient with ITP who was diagnosed with a synchronous development of GIST and early gastric cancer of the stomach. He underwent an elective subtotal gastrectomy with splenectomy. We discuss whether the development of GIST in the stomach in concert with early gastric cancer is an incidental coexistence or involve the same carcinogenic agents. Furthermore, it is not known whether or not such a situation is connected with ITP. To our knowledge this is the second report of a small GIST concomitant with an early gastric cancer and the first one in a patient with ITP.