Congenital self-healing reticulohistiocytosis. Report of the seventh case with histochemical and ultrastructural studies.

A new case of congenital self-healing reticulohistiocytosis was studied with S-100 antibody and electron microscopy. Many tumor cells were S-100-positive and contained Langerhans cell (LC) granules and concentrically laminated dense bodies. Octopus-like bodies and wormlike bodies were also found. The formation of LC granules at the cytomembrane was frequently found, not only between the cytomembrane and its own villi, but also between the cytomembranes of adjoining cells. These findings strongly support the cytomembrane origin of LC granules in general.