Pulmonary Artery Angiomatoid Fibrous Histiocytoma Mimicking a Large Pulmonary Embolism.

A 39-year-old man presented with progressive dyspnea and lower extremity edema. Doppler ultrasound demonstrated bilateral leg partially occluded venous thromboses. A V/Q scan revealed a mismatched perfusion defect involving the entire right middle and lower lobes. Subsequent CT pulmonary angiogram revealed a mass lesion occluding the right interlobar pulmonary artery. Endobronchial ultrasound-guided fine-needle aspiration of the mass was concerning for neoplasm. 18 F-FDG PET/CT demonstrated marked hypermetabolism of the mass lesion. Patient underwent transmediastinal right pneumonectomy with histopathologic diagnosis of pulmonary artery angiomatoid fibrous histiocytoma, a rare etiology mimicking large pulmonary artery embolism.