Mast cell "densities" in vascular proliferations: a preliminary study of pyogenic granuloma, portwine stain, cavernous hemangioma, cherry angioma, Kaposi's sarcoma, and malignant hemangioendothelioma.

The "densities" of mast cells (MCs) in six kinds of vascular proliferation, pyogenic granuloma, portwine stain, cavernous hemangioma, cherry angioma, Kaposi's sarcoma, and malignant hemangioendothelioma (MHE), measured per mm2 were studied using respective specimens prepared with tryptase stain and a personal computer. The average densities of MCs in pyogenic granuloma and MHE were 103.5 +/- 25.2/mm2 (n = 10) and 106.3 +/- 40.2/mm2 (n = 10) [mean +/- standard deviation (SD)]; that in normal skin was 6.85 +/- 4.9/mm2 (n = 20) (mean +/- SD). is a significant difference [t-test (p < 0.0001) and Wilcoxon-test (p < 0.01)]. The results in portwine stain (n = 4), cavernous hemangioma (n = 9), cherry angioma (n = 4), and Kaposi's sarcoma (n = 4) were 68.6 +/- 28.9/mm2, 105.7 +/- 56.9/mm2, 85.3 +/- 45.6/mm2, 82.2 +/- 28.4/mm2 (mean +/- SD), respectively, all of which were greater than that in normal skin by a simple comparison. The results of immunofluorescence microscopy were positive with basic fibroblast growth factor staining in the tissues of pyogenic granuloma, Kaposi's sarcoma and MHE. These facts may morphologically indicate a role of MCs in the angiogenesis of these vascular tumors.