Ameloblastoma with stromal multinucleated giant cells.

We report a case of ameloblastoma which uniquely showed heavy osteoclast-like giant cell accumulation and woven bone formation in the surrounding fibrous stroma. Immunohistochemistry showed that the giant cells were non-epithelial in origin and suggested that stromal factors (i.e., the presence or absence of mineralized bone) determines whether these cells express an osteoclastic antigenic phenotype.