“…Hemothorax is caused by chest trauma [1], iatrogenic bleeding due to medical intervention with insertion of a central venous line [2], thoracentesis [3], pleural biopsy [4], catheterization [5], anti-coagulant treatment [6], spontaneous bleeding due to aortic dissection or aneurysm [7], malignancies [8], endometriosis [9], ruptured bleb in pulmonary emphysema, hematological disorders such as hemophilia [10], and pulmonary infarction [11]. In very rare instances, arteriovenous malfomations (AVMs) as seen in OslerWeber-Rendu syndrome (hereditary hemorrhagic telangiectasia, HHT) may constitute the source of bleeding.…”