Immunophenotype of Dental Implant-Associated Peripheral Giant Cell Reparative Granuloma in a Representative Case Report
We report the case of a 74-year-old white male patient who had worn an overdenture for the previous 6 years, retained by 4 screwed implants and a bar, who presented with an exophytic multilobed lesion of 2.5 × 2.0 cm on the anterior aspect of 1 implant neck, which was surrounded by pink-reddish tissue. All of the soft tissue around the implant was removed until the periosteum was reached. Histologic examination of the lamina propria revealed a cellular proliferation with imprecise boundaries, dense stromal component composed of spindle- to round-shaped mononucleated cells (fibroblasts and monocytes/macrophages), abundant multinucleated giant cells surrounding microscopic hemorrhagic foci, and deposits of hemosiderin; the diagnosis was peripheral giant-cell reparative granuloma (PGCG). Giant cells share the immunohistochemical expression of monocyte/macrophage markers (CD68, calprotectin [Mc387]) and osteoclastic cell markers (tartrate-resistant acid phosphatase, cathepsin K, and microphthalmia-associated transcription factor). After 6 months of follow-up, no bone resorption or recurrence of implant loss was observed. There have been only 12 case reports on dental implant–associated PGCG. Research results to date indicate that there may be little difference in immunophenotype among the giant cells of PGCG, central giant cell reparative granuloma, and peri-implant osteolysis. In conclusion, the immunohistochemical study confirms an osteoclast like giant cells phenotype differentiation in PGCG.
(a) Clinical appearance of the lesion. Note the different colorations of the lesion and the yellow lines, suggesting hemosiderin deposition. (b) Fragments of the lesion, taken for biopsy purposes, including healthy margins. (c) Relationship with the implant neck. Note that the periosteum has not been removed or curetted. (d) Follow-up of the healed tissue at 4 weeks; the bar has been reinstalled.
and 3. Figure 2. (a) Digital panoramic radiography of the patient. No marginal bone loss related to this implant (asterisk), ruling out peri-implantitis. These implants were placed in a healed bone after inflammatory cyst removal, 10 years previously. (b) Detail of the marginal bone loss in periapical radiography of the affected implant. Figure 3. (a) Panoramic photomicrograph of peripheral giant cell granuloma showing an epithelium-coated lobed mass with focal ulceration (hematoxylin and eosin, under magnifying glass). (b) A higher magnification showing spindle-shaped and round mesenchymal cells, highly vascularized areas, hemosiderin deposits, and numerous multinucleated giant cells (hematoxylin and eosin, original magnification ×40).
Immunophenotype expression of peripheral giant cell granuloma. Intense immunohistochemical staining of (a) tartrate-resistant acid phosphatase, (b) cathepsin K, (c) microphthalmia-associated transcription factor, (d) cytoplasmic p63, and variable expression of monocyte/macrophage markers: (e) intense CD68 positivity and (f) scattered calprotectin and (g) CD14 positivity in giant cells and mononuclear cells of peripheral giant cell granuloma. (h) CD34 intense positivity in endothelial cells and weak positivity in giant cells (original magnification ×20).
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