Vascular degeneration in adenomatoid odontogenic tumour: an ultrastructural study

The blood vessels in 3 cases of adenomatoid odontogenic tumour (AOT) were investigated ultrastructurally. An estimated 70-90% of the blood vessels found in the stroma showed degenerative changes which affected both the endothelial lining and the perivascular connective tissue. These vessels showed multiplication of basal lamina and were also encircled by concentric lamellae consisting either of collagen or fine filaments measuring 5-15 nm in diameter. Degradation of the layered collagen into fine filaments similar to those forming the concentric layers was observed. The present results suggest that the fine filaments of the concentric lamellae probably result from degradation of the layered collagen surrounding these vessels.