The ultrastructure of lymphatic vessels in the human middle ear with cholesteatoma.

Lymphatic vessels were few in the edematous portion of the cholesteatoma perimatrix of the human middle ear. But the lymphatic vessels contained mucus and consisted of degenerated endothelial cells. Edema of the perimatrix was considered to be caused by the degeneration of lymphatic vessels. Normal lymphatic vessels were found in the fibrous perimatrix, while macrophages infiltrated and phagocytosed cell debris. In addition, regenerating blood vessels were observed. Degeneration of connective tissue due to lymphatic edema and its repair were both present in the perimatrix. The degeneration of perimatrix was hypothesized to be caused by confined mucous epithelium behind the cholesteatoma matrix.