Recurrent spontaneous massive hemothorax from intrathoracic extramedullary hematopoiesis resulting in respiratory failure.

Extramedullary hematopoiesis (EMH) is a compensatory response to many chronic anemic disorders. Intrathoracic EMH, usually presenting as paravertebral masses over the posterior mediastinum, is a rare entity and is usually asymptomatic. Hemothorax is a rare but possibly fatal complication. Local radiation for intrathoracic EMH is considered effective in preventing its recurrence. Here we describe a patient who had had α-thalassemia for many years and developed a spontaneous left-sided hemothorax from EMH. A chest film and a chest computed tomography (CT) scan had showed multiple paravertebral masses over the lower thoracic spine with left-sided pleural effusion. A pathological diagnosis of EMH was made by video-assisted thoracoscopic surgery. The patient had not received preventive local chest radiation. Ten years later, he suffered from a life-threatening hemothorax complicated by acute respiratory failure without traumatic history. A CT scan showed posterior mediastinal masses over the lower thoracic spine with right-sided pleural effusion. Thoracoscopy was performed to remove the blood clot in the pleural space for successful weaning from mechanical ventilation. This is the first case of intrathoracic EMH to have recurrent hemothorax associated with acute respiratory failure.