Mast cells in an angiosarcoma complicating xeroderma pigmentosum in a 13-year-old girl.

A cutaneous angiosarcoma, a rare tumor that occurs almost exclusively in sun-exposed skin of individuals older than 50 years, developed in an adolescent with Xeroderma pigmentosum (XP). As this is the second report of a child with angiosarcoma and XP, ultraviolet-induced DNA damage may be involved in the pathogenesis of this tumor. Strongly increased numbers of mast cells were found, particularly in the peripheral tumor area, which may reflect with the requirement of mast cells for the growth of vascular structures or a role for mast cells in the antitumor immune response.