Pulmonary embolism in classical meaning is a complication of deep vein thrombosis (usually in the leg veins), developing after a part of the thrombus dislodged and got wedged in pulmonary arteries. However, in half of the patients with pulmonary embolism, deep vein thrombosis is not found. One potential explanation is a different, less common location of the thrombus or previous complete embolization of the whole thrombotic mass. Another possibility is pulmonary artery thrombosis in situ, which is a specific clinical entity associated with some typical risk factors. It develops in the place of vascular injury, as a consequence of hypoxia, inflammatory changes, endothelial dysfunction and injury. Pulmonary artery thrombosis in situ can be a complication after lung resection, radiation therapy, chest trauma, in the patients with Behçet´s disease, sickle cell anemia, chronic obstructive pulmonary disease, tuberculosis or covid pneumonia. Pulmonary artery thrombosis in situ may differ from classical pulmonary embolism in prognosis as well as in therapeutic approach.
Keywords: Deep vein thrombosis; Pulmonary embolism; anticoagulation; deep vein thrombosis; pulmonary artery; pulmonary embolism.