Necrobiotic xanthogranuloma (Q92409)

Necrobiotic xanthogranuloma (NXG) is a rare multisystem histiocytic disease involving the skin in which widespread infiltrated xanthomatous nodules and plaques are associated in the majority of cases with paraproteinaemia and a variety of underlying lymphoproliferative disorders including myeloma. NXG differs from diffuse normolipidaemic plane xanthomatosis in that the skin lesions are palpably infiltrated and elevated rather than flat and diffuse and in that necrobiosis and Touton giant cells are present histologically.