of Pathology, Hospital de

Aim: To investigate whether extracutaneous infantile haemangioma-like tumours are immunohistochemi-cally similar to cutaneous infantile haemangiomas. Methods: Mammary, salivary gland, liver (one each), and placental (two cases) capillary haemangiomas and typical examples of cutaneous (eight cases) infantile haemangioma were investigated immunohis-tochemically for a smooth muscle actin and Glut1, a proposed marker for the skin localised lesion. Positive internal controls included red blood cells, perineurium, trophoblast, and endothelial cells of the placental capillaries. Extralesional vessel endothelium acted as a negative control (except in the placenta). The liver haemangioma and both chorioangiomas presented in patients with Beckwith-Wiedemann syndrome. Results: The endothelial cells of all the vascular lesions were Glut1 positive. These were consistently surrounded by a rim of a smooth muscle actin positive pericytic cells. Controls reacted appropriately. Conclusions: All infantile haemangiomas were immunohistochemically positive for Glut1: expression of this molecule was not limited to infantile haemangiomas of the skin. These tumours comprise proliferations of both endothelial and pericytic cells. The association with Beckwith-Wiedemann syndrome may provide a clue to the molecular genetics of infantile haemangioma.