Explanation for different behavior of peripheral and central giant cell granuloma by CD44 and CD34 immunostaining

AIM: Despite their histopathological similarity, unlike peripheral giant cell granuloma (PGCG), central giant cell granuloma (CGCG) is an osteolytic lesion. Low motility of osteoclasts as bone-resorbing agents decreases osteolysis where CD44 plays a role. The lesion requires angiogenesis to grow which in turn may cause bone resorption. This study aims to compare CD44 and CD34 expression in PGCG and CGCG. METHODS: 30 PGCG (group A) and 30 CGCG (group B) including non-aggressive (B1, N = 14) and aggressive (B2, N = 16) subgroups were evaluated for CD44 and CD34 expression through immunohistochemistry. RESULTS: CD44 staining intensity distribution (SID) score and CD44 labelling index (LI) in PGCG were significantly higher than those in CGCG, while microvessel density assessed by CD34 (MVD-CD34) was significantly higher in CGCG compared with PGCG. CD44-SID score and CD44-LI were higher for B1 whereas MVD-CD34 was higher for B2 (P < .05). CONCLUSION: Different CD44 expression among the studied groups may be indicative of the different motility of osteoclastic giant cells which may influence bone resorption. Lower CD44 expression probably indicates higher osteoclastic giant cell motility in CGCG, which with its higher angiogenesis may explain the different clinical behavior of CGCG compared with that of PGCG.