Electron microscopic study of previously irradiated scleroma.

Nasal biopsies from 2 scleroma patients who had received previous X-ray therapy were investigated under the electron microscope. In the lamina propria, the majority of Mikulicz cells contained numerous small vacuoles. This was attributed to the effect of X-ray therapy causing temporary suppression of the inflammatory process followed by new granuloma formation. The vacuoles of the Mikulicz cells contained some fine granular and fibrillar material of unknown origin. Rounded electron-dense bodies with microprojections on their surface were present near some Mikulicz cells. These structures were considered to be Russell bodies. Occasional small lymph vessels with obstructed lumina were seen. This might indicate the rare spread of Klebsiella rhinoscleromatis bacilli to regional lymph nodes.