Abstract
We present a very rare case of spontaneous hemothorax which was caused by carcinoma of unknown primary. To the best of our knowledge, there are no other such cases reported worldwide. The patient was 72-year-old male who was referred to our department for massive hemothorax. We undertook surgical treatment for haemostasis, and found multiple tumours which led to the diagnosis of carcinoma of unknown primary as the cause of haemorrhage. The tumours increased and grew rapidly after surgery and hemothorax progressed despite our treatment. The patient died from disseminated intravascular coagulation caused by continuous bleeding on postoperative day 19.