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A Nonulcerated, Slowly Growing Mass of the Mandible

Case Challenge Number: 47

Diagnostic Information

History of Present Illness The patient reported that the lesion had been enlarging slowly for the past 21 years. The mass was not tender and the patient did not recall any history of trauma. No other information was available. Medical History The patient’s medical history was unremarkable. He denied alcohol and tobacco use. Clinical Findings The clinical exam revealed a 3×2 cm “bony hard” swelling of the right mandible buccal to #27 and #28. The overlying mucosa was intact and no lingual extension was noted (Figure 1). The remainder of the oral cavity was within normal limits.

Figure 1. Firm, nonulcerated mass of the right mandibular gingiva.

Radiographic Findings The periapical radiograph demonstrated a well-defined mixed radiolucent/radiopaque lesion that caused divergence of the roots without resorption. An occlusal radiograph also revealed buccal expansion and scattered opacifications (Figures 2 and 3).

Figure 2. Periapical radiograph demonstrating a mixed radiolucent/radiopaque lesion between teeth numbers 28 and 29.

Figure 3. Mandibular occlusal radiograph demonstrating the mixed radiolucent/radiopaque nature of this lesion.

Biopsy Findings On microscopic examination, the multiple sections examined revealed islands, strands, and sheets of polyhedral epithelial cells containing mildly pleomorphic nuclei set in a deeply eosinophilic cytoplasm (Figures 4-6).

Hyalinized, eosinophilic amorphous material was noted throughout the stroma. Basophilic calcifications composed of concentric rings also were identified (Liesegang rings). The lesion also demonstrated positive staining with Congo Red and apple/green birefringence under polarized light, a staining pattern consistent with amyloid (Figures 7 and 8).

Figure 7. Low power photomicrograph demonstrating positive staining with Congo Red.

Figure 8. Congo Red stain with polarized light showing apple/green birefringence.