Reactive angioendotheliomatosis in an infant

Reactive cutaneous angioendotheliomatosis (RCA) is an uncommon benign disea se characterized by intravascular proliferation of endothelial cells. The o bservation of RCA in infants is exceedingly rare. We describe a case of RCA in a 3-month-old infant. The lesions were characterized by six small purpu ric papules (1-2 mm in diameter), distributed on the thighs: and neck. The general condition of the patient was good, with no lymphadenopathy, systemi c involvement or fiver. The histo pathologic features of a papule were char acterized by the presence of cohesive aggregates of large mononucleated cel ls protruding into the lumina of dilated vessels and filling some of them c ompletely. Neither an inflammatory infiltrate nor a proliferation of pericy tes were present around blood vessels. Intravascular proliferating cells de monstrated positive staining for Ulex europaeus agglutinin 1 (UEA-1) and fo r Factor VIII-RA and CD34 antigens. The course of the disease was unremarka ble with persistence of the lesions for 8 months: no treatment was started.