Contributed by Jeremie Berdugo MD1, Elizabeth Bilodeau DMD, MD, MsEd2
1Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
2Department of Diagnostic Sciences, University of Pittsburgh School of Dental Medicine, Pittsburgh, PA, USA
A preadolescent male presented to a dental clinic with an asymptomatic swelling in the oral cavity at the level of tooth 38 (International Standard Organization Designation System). His dental history was significant for macrodontia. Panoramic radiograph revealed a well circumscribed and corticated radiolucency (2.2cm x 2.0cm) of the left posterior mandible in the area of the angle to ramus with a faint band of central opacity.
Macroscopically, the nodule was well circumscribed and solid. On microscopic examination, the majority of the tumor was composed of a myxoid stroma with low cellularity, reminiscent of dental papilla (Figure 1). Focally, strands of collagen were present. The stromal cells were spindle to stellate-shaped with rare mitoses. This mesenchymal component was entirely surrounded by a single-layered epithelium with reverse nuclear polarity, and stellate reticulum was focally present on the external aspect of this epithelium (Figure 2). Nests of epithelium were also found within the stroma in association with stellate reticulum (Figure 3). Finally, partially mineralized eosinophilic hard tissue (dentinoid) as well as cementum-like material was present (Figure 4).