An unusual cause of tree-in-bud pattern: pulmonary intravascular tumor embolism caused by chondrosarcoma.

We report the case of a 45-year-old man who initially presented with chondrosarcoma of the left femur that was treated surgically. Follow-up chest computed tomography (CT) performed 3 years later showed multiple small nodules with a tree-in-bud branching pattern and larger elongated opacities with beaded contours. These findings raised the suspicion of intravascular tumor embolism. Pulmonary CT angiography demonstrated intravascular thrombosis and dilated and beaded peripheral pulmonary arteries. The tumoral origin of the thrombus was confirmed by lung biopsy.