Cytomorphometric and immunohistochemical comparison between central and peripheral giant cell lesions of the jaws Gloria Amparo Flórez-Moreno, DDS, a Marcela Henao-Ruiz, DDS, b Diana Marcela Santa-Sáenz, DDS, b Diego Andrés Castañeda-Peláez, DDS, c and Sergio Iván Tobón-Arroyave, DDS, d Medellín, Colombia FACULTY OF DENTISTRY, UNIVERSITY OF ANTIOQUIA Objective. To determine whether cytomorphometric differences of multinucleated giant cells (MGCs) and CD68 reactivity of both MGCs and infiltrating macrophages may be associated with the clinical behavior of central and peripheral giant cell lesions of the jaws. Study design. Paraffin-embedded samples of central giant cell lesions (CGCLs; n = 20) and peripheral giant cell lesions (PGCLs; n = 20) were prepared for cytomorphometric analysis and immunohistochemistry. Results. The nuclei in CGCLs were more numerous, larger, and more irregular than those in PGCLs. Furthermore, CD68 expression and the ratio of CD68 + macrophage to MGCs were significantly greater in CGCLs than in PGCLs. Statistical correlations between CD68 expression and the staining-intensity distribution score within the diagnostic groups were significant in CGCLs and not significant in PGCLs. Conclusion. Although the CGCLs share some histopathologic similarities with PGCLs, differences in both nuclear morphometric parameters of MGC and CD68 immunoreactivity may underlie the distinct clinical behavior. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2008;105:625-32) Central and peripheral giant cell lesions of the jaws are relatively uncommon benign reactive disorders, which arise either peripherally in periodontal ligament and mucoperiosteum of the alveolar ridge, or centrally in the bone. Both are virtually identical histologically, being characterized by the presence of numerous multinucleated giant cells (MGCs) and mononuclear cells (fibroblast- and histiocyte-like cells and monocyte-macrophages) within a prominent fibrous stroma. 1 However, despite their similarity, central giant cell lesions (CGCLs) and peripheral giant cell lesions (PGCLs) have a distinct clinical behaviour. Whereas the PGCLs may rarely cause bone or tooth resorption 2,3 and have a low recurrence rate, more frequently CGCLs have an aggressive behavior characterized by rapid growth, pain, root resorption, bone destruction, and tendency to recur after excision. 4-6 Notwithstanding the clinical differences, it remains unclear if PGCL is either a discrete entity or a peripheral variant of the CGCL. 7,8 Efforts have been made to evaluate if such differences are supported by a distinct pattern of proliferation marker expression in MGCs 8 and the characteristics of cellular lineage from which they are formed. 9 However, it is difficult to draw firm conclusions, because the number of studies concerning differences among these lesions is too limited. 8-10 Moreover, not only the histogenesis of MGCs, but also the mechanism whereby they accumu- late and contribute to the osteolysis that occurs when the lesions arise either within bone or adjacent to bone are still controversial. Cytomorphometric analysis appears to be an efficient and acceptable method of examining features such as structural and morphologic quantitative characteristics of cells and tissues in 2-dimensional planes, and it can allow the identification of variations from the norm, making possible objective and reliable information to be acquired. 11,12 This method has been applied for assessing certain structural alterations of the cells in normal and abnormal tissues, including giant cell le- sions (GCLs). 13-15 Furthermore, various studies have quantified some cellular and nuclear parameters as pos- sible histologic predictors of biologic behavior to es- tablish criteria for the diagnosis of the aggressive vari- ants. 14,16,17 Currently, the application of quantitative Supported by the Research Development Committee of the Univer- sity of Antioquia (CODI 8700-10381). a Specialist in Biomedical Basic Sciences/Histology; Assistant Pro- fessor, Department of Integrated Basic Studies. b Oral and Maxillofacial Surgeon, Department of Oral and Maxillo- facial Surgery. c Research Associate, Laboratory of Immunodetection and Bioanaly- sis. d Stomatologist and Oral Surgeon; Titular Professor; Head and Chair- man of the Laboratory of Immunodetection and Bioanalysis; Advisor of Technical Research Council. Received for publication Apr 23, 2007; returned for revision Aug 1, 2007; accepted for publication Aug 27, 2007. 1079-2104/$ - see front matter © 2008 Mosby, Inc. All rights reserved. doi:10.1016/j.tripleo.2007.08.032 625