Ameloblastoma is a locally aggressive, epithelial odontogenic tumor involving 
mandibles and maxillas. Distant metastasis is a very rare condition and is 
designated as metastasizing (malignant) ameloblastoma despite its benign 
histological appearance. Up to now, only 27 well-documented cases of 
metastasizing ameloblastomas are reported in the literature, and lung is the 
most commonly involved organ. In previous reports of pulmonary metastasizing 
ameloblastomas, there was little description of the histopathologic finding. 
Here, the authors report 2 cases of pulmonary metastasizing ameloblastomas with 
special emphasis on their interesting, interstitial spread along alveolar septa, 
resulting in a unique 2-cell pattern under microscopic examination. Pulmonary 
metastasizing ameloblastoma may pose difficulty in diagnosis if the pathologist 
is not aware of patient's clinical history of ameloblastoma.