A slow-growing, painless swelling of the posterior mandible shows a multilocular radiolucency on X-ray. What is the classic diagnosis to consider? Ameloblastoma is the classic consideration — a benign odontogenic tumor that grows slowly and painlessly but infiltrates surrounding bone, hence 'locally aggressive'. The soap-bubble X-ray pattern reflects multiple bony compartments. Students learn this pattern because early recognition changes the extent of surgical planning.