Non-Langerhans cell histiocytosis represents a broad group of different disorders characterized by the proliferation of histiocytes other than Langerhans cells. One of which, is multicentric reticulohistiocytosis shown here in this middle-aged woman with yellow-pink papules and nodules (with scleral involvement). Multicentric reticulohistiocytosis has subtype (multiple reticulohistiocytomas) that is restricted to skin. It is possible that the diffuse, purely cutaneous form is an early stage of multicentric reticulohistiocytosis before the appearance of joint and other lesions. In multicentric reticulohistiocytosis the onset of arthropathy, may precede, follow, or accompany the onset of skin lesions. No treatment is of consistent value for this disease.
The multinucleate giant cells (the hallmark of the disease) have 3-10 or more nuclei, which may be placed haphazardly, or along the periphery, or clustered in the centre of the giant cell. They contain variable amounts of lipid and free or esterified cholesterol.
Severe involvement of the face may lead to a leonine facies. Does this disease show Köbner (Koebner) response? What are the diseases that may lead to a leonine facies?