Familial sea-blue histiocytosis with cutaneous involvement. A case report with ultrastructural findings

A 25-year-old man presented with the sea-blue histiocyte syndrome. In addition to hepato-splenomegaly, lung infiltrate and bone marrow involvement, he had cutaneous nodules and plaques over his face, and thickened eyelids. Typical sea-blue histiocytes were found in the skin biopsy. Electron microscopy showed cytoplasmic bodies revealing a peculiar pleomorphic structure. A sister suffered from the same disease. This is the first familial case of sea-blue histiocyte syndrome showing cutaneous involvement.