Tubuloreticular structures in the orbicularis oculi muscle of the human eye.

Tubuloreticular structures (TRS) were observed in the orbicularis oculi muscle of two patients operated on senile inversion of the lower eyelid. The structures formed occasionally loose or solid networks similar as those observed in endothelial cells, blood lymphocytes, fibroblasts and muscle cells in association with viral infections, autoimmune diseases, tumors and other tissue destructions and muscle diseases. The tubuloreticular derive form the plasma membrane by the formation of multiple cavities. Their appearance is interpreted as a specific cellular response.