Vascular Transmigration in Peripheral Giant Cell Lesion: a Case Study on Histogenesis

Peripheral giant cell granulomas (PGCL) have microscopic similarities to other pathologies and their origin remains unclear. In this case, a 47-year-old woman presented with a chief complaint of a "painful bleeding lesion" in the region of the canine teeth with a recent history of tooth extraction. Intraorally, a well-circumscribed, pedunculated, purplish-red nodule was noted on the upper alveolar crest associated with an unstable denture. Periapical radiographs showed superficial bone resorption. The lesion was removed and vigorous curettage was performed. Microscopy revealed an ulcerative, non-encapsulated lesion composed of mononuclear stromal cells, prominent multinucleated giant cells (MGCs), and hemorrhage surrounded by fibrous tissue. Apoptotic MGCs were also noted. Interesting, large vessels in the periphery showed transendothelial migration of MGCs positive for matrix metallopeptidase 9 (MMP-9) and macrophage fusion marker CD44. Further studies are needed to clarify the clinical significance of vascular extension in PGCL.