Ultrastructural changes induced by vinblastine in cutaneous lesions of histiocytosis X.

The ultrastructural examination of the skin lesions of 2 typical patients with subacute disseminated histiocytosis X 12, 24, 36, 48 and 72 hours after the intravenous administration of vinblastine enabled us to observe that, after 12-24 hours, there were numerous Langerhans cells undergoing mitosis which had no spindle microtubules but showed fragments of newly forming nuclear membrane, thus demonstrating that mitosis was arrested in anaphase. Later on, in the Langerhans cells mainly, we observed degenerative phenomena (mitochondrial swelling, perinuclear edema and rupture of the plasma membrane) and, finally, a marked reduction in the number of this type of cells were observed.