Indeterminate cell histiocytosis in a pediatric patient: successful treatment with thalidomide

The 15-year-old male patient presented several 2-6 mm large livid reddish-yellowish, shiny, compact papules on the head, trunk and extremities, which had developed within the last 4 months. Histology showed normal epidermis with dense dermal infiltrate of histiocytes accompanied by few eosinophils, Touton or foamy giant cells. The histiocytes were S100 positive, CD1a negative and did not contain Birbeck granules ultrastructurally. Chest X ray, EEG, skull MRI did not show pathology. Opthalmology, neurology, oto-rhino-laryngology did not reveal alterations. Based upon the clinical symptoms and the histopathology, the diagnosis of indeterminate cell histiocytosis was confirmed. Cryotherapy and cauterization did not stop the progression of the disease, however, under thalidomide treatment no new symptoms developed and the lesions healed with pigmentation.