Primordial odontogenic tumour: report of two cases.

AIMS: Primordial odontogenic tumour (POT) is a rare mixed odontogenic neoplasm that is composed of primitive ectomesenchyme resembling dental papilla, surfaced by odontogenic epithelium resembling inner enamel epithelium, without hard tissue formation. Most reported cases have presented in the posterior mandible as a well-demarcated radiolucency associated with an unerupted tooth in the first two decades of life. The aim of this report is to describe the clinicopathological features of two more cases of POT. METHODS AND RESULTS: Each presented as an asymptomatic well-delineated radiolucency in the mandible in a 15-year-old female and an 18-year-old male, respectively. Both tumours were composed of a proliferation of plump spindle and stellate cells in delicately collagenous and myxoid stroma, surfaced by columnar-squamous epithelial cells with reverse nuclear polarisation at the tumour periphery. In one case, the formation of abortive tooth germ-like structures was noted. This has not been reported previously and supports the hypothesis of the primordial nature of this tumour. Both patients showed no recurrence at 3- and 20-month follow-up, respectively. CONCLUSION: This report describes two additional cases of POT for a total of 11 cases reported in the English language literature.