Зображення 00498. Solitary mastocytoma on the back

A solitary mastocytoma on the back of a young child. The diagnosis can be clinically confirmed by scraping the lesion with a blunt object: the swelling of the otherwise nearly macular tumour is conspicious. Simultaneously the surrounding skin shows a red flush, sometimes generalized. These phenomena result from the liberation of histamine from the mast cells in the tumour.