Profile of vascular markers and CT enhancement of hyaline vascular type Castleman's disease

Blood vessels in lymph nodes (LNs) are unique in comprising both capillaries and high endothelial venules (HEVs). Hyaline vascular type Castleman's disease accompanies robust angiogenesis, but it is unclear how the capillaries and HEVs respond. We retrospectively examined surgical specimens of hyaline vascular type unicentric Castleman's disease patients (n = 24) and control LNs (n = 9). We performed immunohistochemistry of CD 31 for capillaries and MECA-79 for HEVs and calculated their microvascular density. We measured CT enhancement as the ratio of Hounsfield Units (HUs) of the target lesion against muscle compared with microvascular density. The microvascular density of Castleman's disease specimen were (CD 31+) 169.7 +/- 77.6, (MECA-79+) 203.5 +/- 96.7, and the microvascular density of control LNs were (CD 31+) 80.7 +/- 20.1, (MECA-79+) 67.4 +/- 23.7, respectively. The microvascular density of both CD 31(+) (P < 0.001) and MECA-79+ (P < 0.001) was higher in Castleman's disease. A positive correlation existed between CT HU ratio and microvascular density for both markers (CD 31: r = 0.517, P = 0.002; MECA-79: r = 0.521, P = 0.002). Intra-nodal angiogenesis of Castleman's disease involves robust proliferation of not only CD 31(+) capillaries, but also MECA-79(+) HVEs, which each correlated with degree of CT enhancement.