Intracardiac thrombi are a very rare manifestation of Behçet's disease. This manifestation occurs with predilection in young males and rarely reveals BD. It can be isolated, but must necessarily be investigated for other vascular damage, including Pulmonary Artery Aneurysms (PAA) [4]. It usually occurs as part of an already advanced Behçet's disease and it is rarely inaugural. The right ventricle is the preferential site which can be complicated by pulmonary embolism, as is the case of our patient. Prolonged fever or an inflammatory syndrome or even chest pain, hemoptysis or dyspnea corresponding to pulmonary embolism should alert the clinician [5].

The mechanism of occurrence is not clear and would probably be secondary to ischemia’s and endothelial lesions promoting platelet aggregation, or the presence of antibodies directed against an enolase, a target protein on the surface of endothelial cells. [6] Antiphospholipid antibodies found in 18% or the presence of other prothrombotic plasma factors such as protein C and or S deficiency [7], increase in factor VIII, homozygosity for Leyden factor V or mutation of the prothrombin gene [7,8].

Moderate hyperhomocysteinemia has been reported a risk factor for venous or arterial thrombosis in the general population and is associated with deficiencies of vitamins B9, B6, B12. Several publications mentioned higher plasma homocysteine ​​values ​​in patients with active BD compared to control groups, with a significant correlation between hyperhomocysteinemia and possible vascular and ophthalmic damage [9, 10].

The diagnosis is based on imaging, firstly with cardiac ultrasound showing an intracardiac mass more echogenic than blood, heterogeneous and adherent to the wall. The differential diagnosis can arise with primary tumors of the right heart, especially with myxomas. Chest CT angiography, or even cardiac MRI, can also help in the diagnosis. Iridium cardiac scintigraphy can determine the acute or chronic nature of the thrombus. The resolution of the thrombus under anticoagulants constitutes a retrospective diagnostic argument [11]. In fact, in our patient, the regression of the intraventricular thrombus under treatment was an element supporting our diagnosis retrospectively.

Arterial involvement is much rarer; Pulmonary artery aneurysms are most often diagnosed if presenting repeated hemoptysis. Chest radiography is rarely normal and shows rounded parahilar opacities, usually bilateral, sometimes distal [12]. Pulmonary angiography and better yet, CT angiography of the chest can be used to visualize them. The PET-scan can also be indicated in these forms [13], but it remains very expensive. These aneurysms have a very poor prognosis with a mortality of 50% the first year. They can be complicated by rupture leading to death by massive hemoptysis and also aneurysmal thrombosis exposing the patient to a significant risk of pulmonary embolism. In our patient, CT angiography did not demonstrate PAA; pulmonary embolism and right ventricular thrombus did not result in right heart failure, as has been reported in other observations.

Medical treatment is conventionally based on immunosuppressive agents, corticosteroids, colchicine and anticoagulants which have been shown to be effective in several cases with resolution of the thrombus. [14] If medical treatment is ineffective or there is a massive or extensive thrombus, a surgical thrombectomy can be proposed as the case of our patient during his first episode of unresolved intracardiac thrombosis even under medical treatment. Recurrences after surgical treatment are possible and require reinforcement of drug treatment. In certain cases, thrombolysis can constitute an interesting alternative to surgical treatment [15]. In our patient, adding immunosuppressors to the rest of the treatment allowed a complete resolution of the thrombus with good outcome.

Conclusion

Intracardiac thrombosis is a rare complication of Behçet's disease that can simulate an intracardiac tumor. Arterial involvement in this disease is rare with higher mortality. The prognosis is unpredictable due to the onset of severe hemoptysis. In our patient, pulmonary embolism and right ventricular thrombus did not result in right heart failure, with good response and evolution after the strengthening of medical treatment.