Histological findings of a pulmonary hilar lymph node. A, The lymph node exhibits residual nodal tissue and replacement by a vascular tumor (hematoxylin-eosin staining). B, The lesion is composed of well-developed capillaries. Organizing thrombi were identifiable (hematoxylin-eosin staining). C-D, Endothelial cells were positive for factor VIII and CD34 (C, Factor VIII immunostaining; D, CD34 immunostaining).