Progressive nodular histiocytosis: an unusual disorder

Progressive nodular histiocytosis (PNH) is a rare type of non-Langerhans cell histiocytosis of the xanthogranuloma group. Less than 20 cases have been reported. We report here a novel case of PNH with dermoscopic description and post-surgical outcome. Our patient presented with pruritic papules and nodules with progression over two years. Dermoscopic examination of large lesions showed multiple telangiectases without ulceration. There was no mucosal involvement. Histopathological analysis of a papule showed a dermal infiltrate composed of histiocytes and many Touton giant cells; a nodule revealed a dermis occupied by spindle cells arranged in a storiform pattern. The nodules were resected and the largest surgical defect, on the forehead, was corrected with A-T advancement flap. The papules were treated with cryosurgery achieving adequate cosmetic outcome without recurrence.