Increased microvessel density in MF. (A) Skin biopsies from patients with MF (All; n = 23) subdivided into MF stages eczema (n = 13), plaque (n = 8), and tumor (n = 2) and from patients with inflammatory cutaneous diseases (All; n = 24) such as psoriasis (n = 8), atopic dermatitis (AD; n = 8), and pseudolymphoma (Pseudolym; n = 8) were stained by immunohistochemistry with anti-CD31 antibody. The number of CD31-positive microvessels (lumen > 50 μm²) was analyzed by microscopic counting of 5 high power fields at 100× magnification and calculating the mean number of microvessels per mm². Data represent the mean ± SEM. Statistical significance was assessed by 2-tailed Student t test. (B) Microvessel density per mm² (y-axis) positively correlates with mast cell number per mm² (x-axis) in MF patients (n = 23; Spearman r = 0.8855; P < .0001). (C) Psoriasis, magnification 150×. (D) Atopic dermatitis, magnification 150×. (E) Pseudolymphoma, magnification 150×. (F) CTCL, eczema stage, magnification 200×. (G) CTCL, plaque stage, magnification 200×. (H) CTCL, tumor stage, magnification 50×, staining of microvessels with anti-CD31 antibody (brown).