Infantile hemangiomas: speculation on placental trophoblastic origin.

BACKGROUND The unique immunobiology of the placental trophoblast and the increased incidence of hemangiomas in infants born after chorionic villus sampling suggest that an immunologically regulated ectopic focus of trophoblasts could be the cell of origin for proliferative infantile hemangiomas. OBJECTIVE To compare tissue from infantile hemangiomas with that of other vascular lesions for the presence of selected placental trophoblast-specific cellular markers. DESIGN AND PATIENTS Twelve tissue specimens taken from infantile hemangiomas on patients aged 5 days to 2 years were retrospectively confirmed clinically and histologically. Negative controls were similarly confirmed, including 6 pyogenic granulomas and 4 vascular-lymphatic malformations. These tissues were used for immunohistochemical analysis of selected trophoblastic markers including human placental lactogen, placental alkaline phosphatase, and cytokeratins 7, 8, and 17. SETTING Tissue submitted from patients seen at Saint Louis University Department of Dermatology and Cardinal Glennon Children's Hospital in St Louis, Mo, between January 1, 1997, and October 31, 1999. MAIN OUTCOME MEASURE Differential staining for trophoblastic markers in infantile hemangiomas compared with control tissues. RESULTS The 12 infantile hemangiomas were uniformly negative for all markers tested. Control tissues were also negative for these markers. Four of the 5 histochemical markers did recognize specific nonvascular, cutaneous elements: placental alkaline phosphatase stained smooth and striated muscle, cytokeratins 7 and 8 stained eccrine glands, and cytokeratin 17 stained pilosebaceous units. CONCLUSIONS Our results do not support the placental trophoblast as the cell of origin for infantile hemangiomas, but we hope our observations and speculation will stimulate further study of this hypothesis.