Desmoplastic variant of ameloblastoma in Chinese patients.

Desmoplastic ameloblastoma is a rare tumour, and we know of only 43 previously reported cases. We report seven Chinese patients (five men and two women) with the desmoplastic variant of ameloblastoma, which makes up 9% of all ameloblastomas diagnosed during the years 1981-1995. The age ranged from 18 to 68 years (mean 43). Five of the tumours were in the maxilla and two were in the mandible. Five of them were situated anteriorly, the remaining two cases involving both anterior and posterior maxilla. The features of the 42 cases previously reported were reviewed and were compared with those in the present study. Our results differ in that we found a male predominance, wider age range and more tumours in the maxilla. Histologically, this variant of ameloblastoma is characterized by abundant collagenous stroma. Because the epithelial clusters may show prominent squamous metaplasia or may be compressed into thin strands in most areas, the appearance may mimic a squamous odontogenic tumour or odontogenic fibroma. The behaviour of this variant of ameloblastoma is likely to be the same as that of the classic ameloblastoma.