Co-existence of sarcoidosis and pulmonary embolism

Sarcoidosis is a multisystem, granulomatous disease of unknown cause (1).Venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE), is a common condition associated with high morbidity and mortality.VTE risk factors include immobilization, hospitalization, surgery, malignancy, aging, thrombophilic status, and the use of certain drugs (2).Recently, chronic inflammation has been recognized as an independent risk factor for VTE.Chronic activation of coagulation by inflammatory cytokines is believed to be the key pathogenesis behind this association.Epidemiological studies have shown an increased incidence of VTE in a variety of chronic immune-mediated inflammatory disorders such as rheumatoid arthritis, vasculitis, and inflammatory intestinal disease (3).Few previous retrospective and observational studies have suggested an increased risk of venous thromboembolic disease in patients with sarcoidosis.Patients with sarcoidosis have been found to have an increased risk of pulmonary embolism compared to the normal population.Although the exact mechanism is not clear, it suggests that sarcoidosis, like other chronic inflammatory diseases, may lead to hypercoagulability with chronic inflammation (4,5).Macrophages and activated leukocytes increase thrombin activation and fibrin formation in sarcoidosis.There is not enough evidence on the incidence and source of hypercoagulability and hypofibrinolysis in sarcoidosis.The true incidence of concomitant sarcoidosis and VTE is unknown.There are some complications associated with longterm use of corticosteroids for the treatment of sarcoidosis such as presence of vascular granuloma, compression of the pulmonary arteries due to mediastinal or hilar lymph nodes, bidirectional inflammation and coagulation process.It is suggested that presence of comorbidities are responsible for the association of sarcoidosis