Recurrent Primordial Odontogenic Tumor: Epithelium-Rich Variant.

Primordial odontogenic tumor (POT) is a rare, mixed odontogenic neoplasm composed of spindled and stellate-shaped cells in myxoid stroma resembling dental papilla, surfaced by cuboidal-to-columnar odontogenic epithelium. Most POTs present in the posterior mandible as a well-demarcated radiolucency associated with a developing tooth in children and adolescents. POT is treated conservatively with no recurrences documented to-date. To describe the clinicopathological features of a recurrent POT. A 19-year-old female presented with an asymptomatic swelling, and panoramic radiograph revealed a multiloculated radiolucency in the mandibular body and ramus, with buccal and lingual perforation. The tumor was composed of plump spindle and stellate cells in a delicately collagenous and myxoid stroma, surfaced by columnar epithelial cells with reverse nuclear polarization. There was extensive epithelial proliferation forming invaginations within the tumor mass and organoid/enamel organ-like structures with enameloid-like deposits, dentinoid, and dystrophic calcifications. This was similar to the POT that had been excised four years prior from the same location. The patient underwent hemi-mandibulectomy and currently is free of disease at a thirteen-month follow-up. This report describes the first recurrent POT exhibiting extensive epithelial proliferation.