Abstract
Both electron microscopic and light microscopic examinations were performed on 9 specimens of the laryngeal nodule. The specimens were classified into edematous type and fibrous type according to the histopathological findings of submucous structure under light microscopy. The thickening of the basement membrane and active collagen formation were characteristic of edematous type. The edematous type was considered to be in the early stage of the laryngeal nodule, and seemed to be transformed into fibrous type later.
The hemorrhage in epithelial layer was found in one case of the edematous type. The cause of hemorrhage was considered to be the mechanical stimulation produced by nodules striking each other during phonation, and also this mechanical stimulation was probably the cause of edema of the submucosal tissue.
We suggest that mechanical stimulation plays an important role in the formation of the laryngeal nodule because the finding of the submucosal tissue of the nodule in early stage is edema.
