[Growth phenomena of jaw ameloblastomas].

Jaw ameloblastomas produce most frequently (62%) multilocular translucences. An unilocular translucence was observed in 28% of the cases. In both forms, secondary cysts were present. This radiomorphologic finding is of pathognomonic value. Conchiform or finger-shaped translucences were seen in 10% of the cases. Such radiographic changes were observed in ameloblastomas arising from the oral mucosa. The border of the radiolucent area was always sharply defined and had a lobulate or wreathed form. The ameloblastoma spreads in an expansive or invasive way. The bone destruction is in all probability caused by the acid phosphatase activity of the tumour. Bone transformation occurs simultaneously with bone destruction and might be regarded as a morphologic sign of the defence mechanism.