Maxillofacial and axial/appendicular giant cell lesions: unique tumors or variants of the same disease?--A comparison of phenotypic, clinical, and radiographic characteristics

Sclerostin Immunohistochemical Staining in Aggressive Maxillofacial Giant Cell Lesions: Initial Results and Potential Therapeutic Target

INTRODUCTION

Maxillofacial (MF) giant cell lesions (GCLs) are benign, often locally aggressive lesions with potential for recurrence. Systemic treatments have included interferon alpha, calcitonin, bisphosphonates, and denosumab. Sclerostin (SOST) is typically thought to be a negative regulator of bone metabolism and anti-SOST agents have been used to treat osteoporosis; however, its role in central giant cell granuloma is unknown. The purpose of this study was to evaluate the expression of SOST in MF GCLs.

MATERIALS AND METHODS

This was a retrospective study of patients with MF GCLs treated at a single institution between 1993 and 2008 with a minimum follow-up of 6 months. Representative tissue was used to create a tissue microarray and SOST immunohistochemical (IHC) staining and grading was performed. The primary outcomes were IHC staining of the stromal cells and giant cells. The secondary outcomes included correlation of IHC staining and patient predictor variables including clinically benign and aggressive lesions. All analyses were completed using univariate statistical tests.

RESULTS

A total of 37 subjects were included (29 clinically aggressive and 8 clinically benign). Sclerostin staining was present in 30 of 37 subjects (81%). Of these, 22 (60%) had stromal cell staining and 28 (76%) had giant cell staining. The presence or absence of staining, of either cell type, was not associated with aggressiveness, presence of clinical symptoms, tumor size, previous interferon therapy, previous surgery, or the race or age of the patient.

DISCUSSION

Maxillofacial GCLs have an overall high level of SOST staining; however, the role of SOST in treatment and prognosis is unknown and warrants further study.

Educational Case: Giant Cell Tumor of the Bone in Both the Axial and Appendicular Skeleton

The following fictional case is intended as a learning tool within the Pathology Competencies for Medical Education (PCME), a set of national standards for teaching pathology. These are divided into three basic competencies: Disease Mechanisms and Processes, Organ System Pathology, and Diagnostic Medicine and Therapeutic Pathology. For additional information, and a full list of learning objectives for all three competencies, seehttp://journals.sagepub.com/doi/10.1177/2374289517715040.¹

Making sense of giant cell lesions of the jaws (GCLJ): lessons learned from next-generation sequencing

Next-generation sequencing has revealed mutations in several bone-related lesions and was recently used to uncover the genetic basis of giant cell lesions of the jaws (GCLJ). Consistent with their benign nature, GCLJ show a low tumor mutation burden. They also harbor somatic, heterozygous, mutually exclusive mutations in TRPV4, KRAS, or FGFR1. These signature mutations occur only in a subset of lesional cells, suggesting the existence of a 'landscaping effect', with mutant cells inducing abnormal accumulation of non-mutant cells that form the tumor mass. Osteoclast-rich lesions with histological similarities to GCLJ can occur in the jaws sporadically or in association with genetically inherited syndromes. Based on recent results, the pathogenesis of a subgroup of sporadic GCLJ seems closely related to non-ossifying fibroma of long bones, with both lesions sharing MAPK pathway-activating mutations. In this review, we extrapolate from these recent findings to contextualize GCLJ genetics and we highlight the therapeutic implications of this new information. © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Adjunctive Strategies for Benign Maxillofacial Pathology

Benign cysts and neoplasms of the maxillofacial region can vary in behavior, with some growing rapidly and resulting in destruction of surrounding structures. Despite their benign histology, many require often-morbid treatment to prevent recurrence of these lesions. Several less invasive and adjunctive medical treatments have been developed to lessen the morbidity of surgical treatment. As the molecular and genomic pathogenesis of these lesions is better understood, more directed treatments may lessen the burden for patients.

Primary thoracic giant cell tumor of bone sensitive to steroids

Spinal giant cell tumor of bone (GCTB) is a rare benign, but locally aggressive, entity. We report the case of a 40-year-old man diagnosed with GCTB of the thoracic spine. The only symptom upon presentation was progressive back pain with pain radiating to the chest. Magnetic resonance imaging showed that the soft tissue mass extended posteriorly into the spinal canal, causing severe spinal cord compression. We initially treated this case with Decadron (Fresenius kabi, Bad Homburg vor der Hohe, Germany) for 1 week. This led to a reduction of tumor size and decompression of the spinal cord. To the best of our knowledge, there have been no prior reports of primary GCTB sensitive to steroid therapy within the existing literature.

Immune Surveillance Plays a Role in Locally Aggressive Giant Cell Lesions of Bone

BACKGROUND

Giant cell lesions are locally aggressive intraosseous neoplasms with capacity to metastasize. The role of immune surveillance in the pathophysiology of giant cell lesions is poorly understood, and understanding what role the immune system plays in giant cell lesions may lead to the development of more effective treatment. The aim of this study was to explore the role of immune surveillance in giant cell lesions by examining the expression of the HLA class I and class II antigens and tumor infiltrating lymphocytes. In addition, we examined the role of the immune modulating surface antigen B7-H3, which belongs to the B7 superfamily, a group of molecules that modulates T-cell responses.

QUESTIONS/PURPOSES

(1) Is an immune response elicited by giant cell lesions? (2) Do clinically relevant human leukocyte antigen (HLA) defects exist in giant cell lesions? (3) Is B7-H3 a clinically relevant immune modulator?

METHODS

The study sample was derived from the population of patients presenting to the Massachusetts General Hospital for evaluation and management of giant cell lesions from 1993 to 2008. We included patients with histologically confirmed giant cell lesions with a minimum followup of 6 months. Patients with systemic diseases (n = 4 [3%]), syndromes associated with giant cell lesions (n = 4 [3%]), and those without sufficient followup (n = 26 [19%]), inadequate records (n = 7 [5%]), or inadequate tissue available (n = 2 [1%]) were excluded. Tissue microarray, containing 288 tissue cores for 93 patients, was carefully constructed. This contained tissue from 45 patients with maxillofacial lesions, 38 with aggressive and seven with nonaggressive lesions, and 48 patients with axial and appendicular lesions, 30 with aggressive lesions and 18 with nonaggressive lesions. The population mean age was 28 ± 12 years and the duration of followup was 4 ± 3 years. The tissue microarray was immunohistochemically stained with monoclonal antibodies specific for HLA classes I and II and B7-H3 antigens and analyzed for tumor infiltrating lymphocytes. Antigen expression was examined in multinucleated giant cells and mononuclear stromal cells. The results were correlated with local invasion and tumor aggressiveness, which is based on accepted staging criteria.

RESULTS

Tumor infiltrating lymphocytes were detected in all the tumors. The mean number of CD8+ T cell infiltration was lower in aggressive tumors (median, 4.8; interquartile range [IQR], 0.4-13.4), when compared with nonaggressive tumors (median, 15.8; IQR, 4.3-46.3; p = 0.007). HLA class I antigens were highly expressed by multinucleated giant cells in all tumors, but were lightly expressed on mononuclear stromal cells in 53% (45 of 84) to 73% (56 of 77) of tumors. HLA class I antigen low expression in mononuclear stromal cells was associated with tumor aggressiveness (odds ratio [OR], 4.3; p = 0.005). Low HLA class I expression combined with low CD8+ T cell infiltration was most highly associated with tumor aggressiveness (OR, 7.81; p = 0.011). B7-H3 antigen was expressed in 36.9% mononuclear stroma cells and also was associated with local tumor invasion (OR, 1.36; p < 0.001). Similarly, giant cell lesions with high B7-H3 expression and low CD8+ tumor infiltrating lymphocytes were associated with increased tumor aggressiveness (OR, 8.89; p = 0.0491).

CONCLUSIONS

Locally aggressive giant cell lesions are associated with low HLA class 1 antigen expression, low CD8+T cell infiltration, and high expression of the immune modulator B7-H3.

CLINICAL RELEVANCE

Failure of immune surveillance implies that there may be an opportunity to target aspects of the immune surveillance machinery to treat giant cell lesions.

Genetic Analysis of Giant Cell Lesions of the Maxillofacial and Axial/Appendicular Skeletons

PURPOSE

To compare the genetic and protein expression of giant cell lesions (GCLs) of the maxillofacial (MF) and axial/appendicular (AA) skeletons. We hypothesized that when grouped according to biologic behavior and not simply by location, MF and AA GCLs would exhibit common genetic characteristics.

MATERIALS AND METHODS

This was a prospective and retrospective study of patients with GCLs treated at Massachusetts General Hospital from 1993 to 2008. In a preliminary prospective study, fresh tissue from 6 aggressive tumors each from the MF and AA skeletons (n = 12 tumors) was obtained. RNA was extracted and amplified from giant cells (GCs) and stromal cells first separated by laser capture microdissection. Genes highly expressed by GCs and stroma at both locations were determined using an Affymetrix GeneChip analysis. As confirmation, a tissue microarray (TMA) was created retrospectively from representative tissue of preserved pathologic specimens to assess the protein expression of the commonly expressed genes found in the prospective study. Quantification of immunohistochemical staining of MF and AA lesions was performed using Aperio image analysis to determine whether immunoreactivity was predictive of aggressive or nonaggressive behavior.

RESULTS

Five highly ranked genes were found commonly in GCs and stroma at each location: matrix metalloproteinase-9 (MMP-9), cathepsin K (CTSK), T-cell immune regulator-1 (TCIRG1), C-type lectin domain family-11, and zinc finger protein-836. MF (n = 40; 32 aggressive) and AA (n = 48; 28 aggressive) paraffin-embedded tumors were included in the TMA. The proteins CTSK, MMP-9, and TCIRG1 were confirmed to have abundant expression within both MF and AA lesions. Only the staining levels for TCIRG1 within the GCs predicted the clinical behavior of the MF lesions.

CONCLUSIONS

MMP-9, CTSK, and TCIRG1 are commonly expressed by GCLs of the MF and AA skeletons. This supports the hypothesis that these lesions are similar but at different locations. TCIRG1 has not been previously associated with GCLs and could be a potential target for molecular diagnosis and/or therapy.

Proceedings of the American Association of Oral and Maxillofacial Surgeons 2015 Research Summit

The Fifth Biennial Research Summit of the American Association of Oral and Maxillofacial Surgeons and its Committee on Research Planning and Technology Assessment was held in Rosemont, Illinois on May 6 and 7, 2015. The goal of the symposium is to provide a forum for the most recent clinical and scientific advances to be brought to the specialty. The proceedings of the events of that summit are presented in this report.

Pediatric Vascular Tumors of the Head and Neck

Oral and maxillofacial surgeons are often involved in the diagnosis and treatment of vascular neoplasms of the head and neck. An incorrect diagnosis may lead to improper or unnecessary treatment. This article reviews the diagnosis and management of vascular tumors.

Do histologic criteria predict biologic behavior of giant cell lesions?

PURPOSE

To determine whether the clinical behavior of giant cell lesions (GCLs) or their anatomic location can be differentiated by histologic criteria alone.

MATERIALS AND METHODS

We performed a retrospective study of patients with GCLs treated at Massachusetts General Hospital between 1993 and 2008. Predictor variables were histologic parameters: number of giant cells (GCs) per high-power field, number of nuclei per GC, GC size, stromal cellularity, stromal type, presence of hemorrhage and reactive osteoid, and blinded pathologists' prediction of location and behavior. Outcome variables were clinical behavior (aggressive or nonaggressive) and GCL location, that is, maxillofacial (MF) or axial/appendicular (AA). Descriptive and bivariate statistics were computed with statistical significance set at P ≤ .05.

RESULTS

The sample included 88 subjects: 41 MF GCLs (35 aggressive) and 47 AA GCLs (28 aggressive). Aggressive AA lesions had more GCs per high-power field, larger mean GC size, and increased stromal cellularity, and they more frequently had a mononuclear stroma when compared with aggressive MF lesions (P < .05). There were no significant histologic differences between aggressive and nonaggressive MF lesions or between nonaggressive MF and nonaggressive AA lesions. Aggressive AA lesions had more nuclei/GC than nonaggressive AA lesions (P = .03). Using histologic criteria only, blinded pathologists predicted clinical behavior in only 45% of cases (κ = 0.19, P = .09). They predicted a lesion's location in 82% of cases with fair agreement (κ = 0.44, P < .01).

CONCLUSIONS

Results of this study indicate that histologic differences between aggressive and nonaggressive GCLs are insufficient for pathologists to differentiate them consistently regardless of location.

Overexpression of matrix metalloproteinase (MMP)-1 and -9 in central giant cell lesions of the jaws: implications for clinical behavior

OBJECTIVE

The aim of this study was to investigate the relationship between the immunohistochemical expression of MMP-1 and MMP-9 with the clinical behavior of central giant cell lesions (CGCLs) of the jaws.

STUDY DESIGN

Paraffin-embedded tissue from 30 aggressive and 12 nonaggressive CGCLs was assessed for the expression of MMP-1 and MMP-9 using immunohistochemistry.

RESULTS

Although cellular immunolocalization patterns of MMP-1 and MMP-9 were similar, mean values of expression estimation/SID scores of each protease were significantly higher in aggressive CGCLs in comparison with nonaggressive lesions. Moreover, linear regression analysis showed that there was a reasonably good correlation not only between the expression estimation but also among SID scores of the 2 proteolytic enzymes.

CONCLUSION

The findings of this study suggest a role for MMP-1 and MMP-9 in the resorptive activity of different cellular groups in CGCLs and indicate that differences in immunoreactivity of these 2 proteolytic enzymes may underlie the distinct clinical behavior.