Pulmonary hypertension secondary to thrombosis of the pulmonary vessels in a patient with the primary antiphospholipid syndrome

Recurrent pulmonary emboli or microthromboses are hypothesized as possible causes of pulmonary hypertension in the antiphospholipid syndrome (APS), but thrombosis of the pulmonary vessels has been rarely documented. We describe the case of a 45-year-old Caucasian man affected by thrombocytopenia, recurrent deep venous thrombosis, recurrent pulmonary embolism and fatal chronic pulmonary hypertension (systolic pressure: 85 mm Hg). Anticardiolipin antibodies were highly positive, and the lupus anticoagulant was present. At autopsy, recent thromboses of small vessels were observed in the lung, with organized clots and recanalized channels. Furthermore, friable and firm vegetations and nodules were observed on the cusps of the mitral and tricuspid valves, intermingled with recent surface fibrinous thrombi. In the adrenals we found vascular thrombotic lesions similar to those in the lungs. The pathological lesions suggest pulmonary hypertension secondary to pulmonary arterial microthromboses. Moreover, this is the first documentation of tricuspid valve pathology in a patient with APS.