Heterogeneity of mast cells derived from different species and anatomic sites has been demonstrated in recent years [1-3]. Increased numbers of cutaneous mast cells have been observed not only in mastocytosis but also in several cutaneous neoplasms, including neurofibromas, and in various inflammatory conditions. In this study, we examined the mast cell population density and histamine content in cutaneous neurofibromas. In addition, the in vitro responsiveness of enzymatically dispersed mast cells obtained from neurofibromas was assessed.