ACQUIRED REGRESSIVE CUTANEOUS NON-X HISTI OCYTOSIS OF CHILDHOOD - ELECTROMICROSCOPY AND IMMUNOCYTOCHEMISTRY

Introduction : Cutaneous histiocytosis of childhood often regresses sp ontaneously without treatment. In some cases however, it is difficult to differentiate agressive forms and electron microscopy and immunohis tochemistry can be a valuable help. We report a case of cutaneous hist iocytosis in a child which illustrates the difficulties encountered in the classification of histiocytosis. Case report : An 18-month old gi rl was brought to consultation with a cutaneous nodule which had devel oped at the age of 15 months on the labia majora. A second nodule on t he chin had regressed spontaneously. Histology showed evidence of derm al histiocyte proliferation. Immunohistochemistry demonstrated its non Langerhans nature which was confirmed by electron microscopy. The cli nical course was benign after surgical exeresis of the lesion on the l abia majora. Discussion : Different forms of histiocytosis can be clas sed on the basis of 4 criteria : Langerhans origin or not, acquired or congenital forms, cutaneous or visceral involvement, benign or malign ant course. Four diagnosis were possible in our case: histiocytosis X, self-healing congenital histiocytosis, benign cephalic histiocytosis, juvenile xanthogranuloma. We prefered to use the descriptive term of acquired regressive cutaneous non-X histiocytosis of childhood.