This document discusses Giant Cell Granuloma Bone Lesions, a rare pathology mainly affecting jaw bones, and its association with Noonan syndrome, a genetic disorder classified as a RASopathy.
Contents
Central Giant Cell Granuloma CGCG
Histological characteristics of CGCG and GCCG
Noonan Syndrome NS
Central Giant Cell Granuloma CGCG
Histological characteristics of CGCG and GCCG
Noonan Syndrome NS
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Extract
[...] Dentistry - Giant Cell Granuloma Bone Lesions in patients with Noonan syndrome Giant Cell Granuloma Bone Lesions Giant Cell Granuloma Bone Lesions form a heterogeneous group of rare pathologies mainly affecting the jaw bones, including the mandible. They consist of multinucleated giant cells resembling osteoclasts, dispersed in a richly vascularized fibroblastic stroma (Bansal et al., 2023). 1 Central Giant Cell Granuloma (CGCG) The WHO defines CGCG as a "localised benign or aggressive osteolytic proliferation, with fibrous tissue, hemorrhage, hemosiderin deposits, giant cells resembling osteoclasts, and reactive bone formation ». [...]
[...] The figure below illustrates the evolution of a jaw GCG that was key to identifying NS (Friedrich et al., 2024). Figure 3.2: Evolution of a CGCG in the jaw panoramic views, 3D imaging The subtotal reossification of the right mandibular angle is visible on the panoramics. discovery in the maxilla, soft tissue swelling after the first resection, persistence of the mass in the maxillary sinus and change in shape formation of the maxillary bone over time and the subsequent development of the upper left wisdom tooth. The tooth shows a significant mesial physical drift in the newly formed bone. [...]
[...] Their morphology and size are variable. - A large quantity of blood vessels Various studies have revisited Jaffe's original hypothesis and concluded that a common pathological process influenced by the patient's age and the site of the event is shared by GCT and GCCG. An immunohistochemical study has shown that the giant cells of GCCG behave like osteoclasts (Flanagan et al., 1998) under the effect of calcitonin hormone. Furthermore, the multinucleated giant cells exhibit all cytochemical elements and functional characteristics of osteoclasts. [...]
[...] They require the action of growth factors secreted by stromal cells, activating osteoclast precursors expressed on the surface of stromal cells, released by proteolysis or secreted. The three main ones are the two cytokines M-CSF, RANK-L and OPG. Figure 3.1: Osteoclastogenesis (After Maurin, 2021) The differentiation of osteoclasts requires several steps from hematopoietic stem cells. The first step is the entry of precursors into the monocyte lineage through proliferation under the effect of M-CSF. Then RANK-L acts to enter the cells into the osteoclast lineage. [...]
[...] - In GCG, VEGF would have a key role in bone resorption. Giant cells derived from mononuclear precursors differentiate into mature giant cells under the effect of the proliferation of stromal cells expressing RANK-L (including osteoblasts derived from stromal cells). Tumor stromal cells induce the recruitment and differentiation of circulating mononuclear precursors into abnormal osteoblasts constituting the giant cells. 3 The Noonan syndrome In NS, gene mutations (PTPN11, SOS1?) involved in the RAS/MAPK signaling pathway classify it as a group of hereditary syndromes called RASopathies (Atotha et al., 2020). [...]
