Infantile hemangiomas - Speculation on placental trophoblastic origin

Background: The unique immunobiology of the placental trophoblast and the i ncreased incidence of hemangiomas in infants born after chorionic villus sa mpling suggest that an immunologically regulated ectopic focus of trophobla sts 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-specifi c cellular markers. Design and Patients: Twelve tissue specimens taken from infantile hemangiom as on patients aged 5 days to 2 years were retrospectively confirmed clinic ally and histologically. Negative controls were similarly confirmed, includ ing 6 pyogenic granulomas and 4 vascular-lymphatic malformations. These tis sues were used for immunohistochemical analysis of selected trophoblastic m arkers including human placental lactogen, placental alkaline phosphatase, and cytokeratins 7, 8, and 17. Setting: Tissue submitted from patients seen at Saint Louis University Depa rtment 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 trophoblastic markers in infant ile hemangiomas compared with control tissues. Results: The 12 infantile hemangiomas were uniformly negative for all marke rs tested. Control tissues were also negative for these markers. Four of th e 5 histochemical markers did recognize specific nonvascular, cutaneous ele ments: placental alkaline phosphatase stained smooth and striated muscle, c ytokeratins 7 and 8 stained eccrine glands, and cytokeratin 17 stained pilo sebaceous units. Conclusions: Our results do not support the placental trophoblast as the ce ll of origin for infantile hemangiomas, but we hope our observations and sp eculation will stimulate further study of this hypothesis.