1. Primary hemangiopericytoma of the trachea
Masataka Yoshida, MD, Masafumi Morita, MD, Shotaro Kakimoto, MD, Manpei Kawakami, MD, Shinjiro Sasaki, MD 
The Annals of Thoracic Surgery 
Volume 76, Issue 3, Pages (September 2003)
DOI: /S (03)

2. Fig 1
(A) Bronchoscopic findings demonstrated that the tumor was occupying most of the tracheal lumen. (B) Some parts of the tumor were cauterized with the neodymium:yttrium–aluminum garnet laser.
The Annals of Thoracic Surgery  , DOI: ( /S (03) )

3. Fig 2
(A) This tumor was rich in capillaries and small vessels with a single layer of endothelium and dense spindle-shaped tumor cells that proliferated around blood vessels in hematoxylin & eosin stain. (B) A silver stain showed the individual tumor cells surrounded by reticular fibers. The tumor cells were clearly positive for (C) vimentin and (D) collagen type IV (all stains, original magnification ×400).
The Annals of Thoracic Surgery  , DOI: ( /S (03) )