Cutaneous Langerhans cell histiocytosis with subsequent development of haematological malignancies. Report of two cases.

Adult cutaneous Langerhans cell histiocytosis (LCH) is a rare disease. We report two cases illustrating the variability of the clinical presentation and the response to treatment. In both cases a remission was achieved: in one case a partial remission with psoralen plus UVA irradiation (PUVA) and methotrexate plus topical corticosteroid ointment; in the other case by treatment with thalidomide. Despite a therapeutic response, both patients later developed haematological malignancies: a chronic myelo-monocytic leukaemia and an acute lymphatic leukaemia. In conclusion, patients with adult cutaneous LCH should be monitored carefully so that a secondary malignancy is not overlooked.