PMC4100273_01
Clinical and radiographic appearances. (a) Frontal view: a fiery red gingival lesion on the labial side of the primary maxillary right central incisor. (b) Occlusal view: the maxillary right primary central incisor was a little palatally displaced. (c) A pulpectomy and restoration had been done for the primary maxillary right central incisor at a local dental clinic. There was no observable radiopaque abnormality in the periapical radiograph.
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During her initial examination in our hospital, we noticed a fiery red gingival mass that neither bled nor felt palpation pain (Figure 1(a)). The tooth was a little palatally displaced but not mobile (Figure 1(b)). The periapical radiograph revealed no periapical lesion, root resorption, or radiopaque abnormality (Figure 1(c)).
Hematoxylin and eosin staining for the gingival lesion. (a) The black arrow indicates a dental papilla-like tissue. (b) The red arrows denote abundant small blood vessels. (c) A large mineralized matrix appears like enamel or dentin structures. (d) There are several islands of odontogenic epithelium. One of them clearly exhibits enamel organ differentiation. Panels (b), (c), and (d) are magnifications (x4) of the white squares of panel (a). Scale bar = 200 mum for panel (a) and 50 mum for panels (b), (c), and (d).
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Abundant small blood vessels surrounded the odontogenic epithelium (Figure 2).
Clinical appearance 1 year after excisional biopsy for the gingival lesion.
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A one-year postoperative follow-up revealed no evidence of recurrence, but only a mild gingival inflammation (Figure 3).
Immunohistochemistry for amelogenin, beta-catenin, CD31, and CD44. The stainings showed that amelogenin, beta-catenin, and CD44 were strongly expressed in the enamel epithelial cells. Some of the stromal cells, leukocytes, and endothelial cells were also positive for CD44 staining. CD31 staining appeared in the endothelial cells of the tumor stroma, especially in the area adjacent to the enamel epithelium. Scale bar = 100 mum for all panels but the bottom right (25 mum).
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CD44 staining. CD31 staining confirmed that there were abundant small blood vessels in the tumor stroma, especially in the area adjacent to the enamel epithelium (Figure 4).