Central giant cell lesion is an uncommon benign jaw lesion, with uncertain aetiology, and variable clinical behaviour. Studies of molecular markers may help to understand the nature and behaviour of this lesion, and eventually may represent a target for pharmacological approaches to treatment. The aim of this study was to analyse the expression of glucocorticoid and calcitonin receptors in central giant cell lesions before and after treatment with intralesional steroid. Paraffin-embedded blocks from patients who underwent treatment with intralesional triamcinolone hexacetonide injections were stained immunohistochemically. Biological material from patients who underwent a surgical procedure after treatment were tested immunohistochemically. 18 cases (9 aggressive and 9 non-aggressive) were included. The difference in calcitonin receptor expression was not statistically significant between the aggressive and non-aggressive lesions and between the patients with a good response and those with a moderate/negative response to treatment. Glucocorticoid receptor expression in the multinucleated giant cells was higher in patients with a good response. It can be postulated that immunohistochemical staining for glucocorticoid receptors may provide a tool for selecting the therapeutic strategy. An H -score greater than 48 for glucocorticoid receptors in multinucleated giant cells predicted a good response in this study.
Central giant cell lesion (CGCL) is an uncommon benign intraosseous lesion found in the maxillofacial region that has variable clinical behaviour. CGCLs have been classified as non-aggressive and aggressive lesions. Most cases present as asymptomatic, slow growing lesions without cortical perforation. Aggressive CGCLs are characterized by rapid growth, pain, bony expansion, root resorption and dental mobility. In aggressive lesions, recurrence is common. The nature of CGCLs is controversial; lesions found after bone trauma, such as dental extraction, point to the reactive nature of CGCLs. Aggressive CGCLs with rapid growth and high recurrence rates are thought to be neoplastic in nature.
Histologically, CGCL is characterized by the presence of multinucleated giant cells (MGCs) in a cellular background composed of mononucleated stromal cells (MSCs) with ovoid or spindle-shaped nuclei. In aggressive lesions, MGCs are usually more numerous, larger and uniformly scattered throughout the lesion. The cellular lineage from which MGCs are derived is controversial. Positive immunohistochemical expression of receptor activator of nuclear factor-kB (RANK), tartrate-resistant acid phosphatase (TRAP), vitronectin receptor (VNR) and calcitonin receptor have suggested an osteoclastic phenotype for MGCs. The presence of CD68 glycoprotein and alpha-1-antichymotrypsin has suggested that MGCs have a macrophage/histiocyte origin.
CGCL is an uncommon lesion that occurs more frequently in females. Although it can be found in all age groups, most cases appear before the age of 30 years. The mandible is more often involved than the maxilla with a mandibular/maxillary ratio of 2:1. In the maxilla, the anterior region is usually affected, whilst in the mandible, the anterior and posterior regions are equally affected.
Traditionally, surgery is the treatment of choice for CGCLs, and the extent of surgery ranges from curettage with or without adjuvant therapy, such as cryosurgery, peripheral ostectomy and carnoy solution, to aggressive en bloc resection, resulting in varying degrees of deformity. Non-surgical methods have been proposed to treat CGCLs, including radiotherapy, systemic calcitonin, intralesional injection with corticosteroids and systemic α interferon. In an earlier report, the authors presented excellent results with intralesional triamcinolone with a good response in 15/21 patients, a moderate response in 4/21 patients and a negative response in 2/21 patients.
The actions of glucocorticoids and calcitonin are mediated, at least in part, via specific glucocorticoids receptors (GR) and calcitonin receptors (CTR). GR and CTR are expressed in CGCLs, which has been previously described ; but no distinction was made in staining characteristics between MSCs and MGCs prior to and after treatment with glucocorticoids. The purpose of this study was to analyse the expression of GR in CGCLs immunohistochemically before and after treatment with intralesional triamcinolone. Also, as Vered et al. demonstrated that the use of calcitonin may influence the expression of GR and CTR, the expression of CTR was also evaluated to determine whether CTR expression could be influenced by intralesional corticosteroid treatment.
Materials and methods
Formalin-fixed paraffin-embedded blocks from 21 consecutive cases of primary CGCLs from patients who underwent treatment with intralesional triamcinolone hexacetonide injections (20 mg/ml diluted in an anaesthetic solution of 2% lidocaine/epinephrine 1:200.000 in a ratio of 1:1; 1.0 ml of the solution infiltrated every 1 cm 3 of radiolucide area of the lesion totalling 6 biweekly applications) were retrieved. 11 were male and 10 female, with ages ranging from 5 to 25 years (median 15.5 years). The mandible was the most frequent localization (13 cases) followed by the maxilla (8 lesions). According to the criteria established by Chuong et al., the lesions from 10 patients were classified as aggressive, and 11 were classified as non-aggressive.
The treatment response was determined using previously determined scores in which four criteria were considered: stabilization or regression of lesion size evaluated clinically and in follow-up radiographs; the absence of symptoms; increased radio-opacity in radiographs, representing peripheral and/or central calcification of the lesion; increased difficulty in solution infiltrating the lesion during the sequence of applications. When a case met all four criteria, the response was determined to be good; meeting two or three criteria was determined to be moderate; and meeting one criterion or no criteria implied a negative response to treatment. On the basis of these criteria, 15 patients had a good response, 4 had a moderate response, and 2 had a negative response. Although these criteria present some subjective topics, such as ‘increased difficulty of the injection’, the treatment is usually performed by the same surgeon so increasing the difficulty of the injection can be measured. This finding is reported by several authors, and it reflects the ossification of the lesion. It is recommended that the surgeon takes notes about the resistance of the injections.
Immunostaining was performed according to a previously described protocol. For antigen retrieval, deparaffinized sections were pretreated by heating in a microwave oven in 10 mM citrate buffer pH 6.0 for 15 min. After cooling, the sections were immersed in phosphate buffered saline (PBS) containing 3% hydrogen peroxide for 10 min to block endogenous peroxidase activity. The sections were then incubated in a humid chamber overnight at 4 °C with the following primary antibodies: anti-glucocorticoid receptor (NCL-GCR; dilution 1:50; Vision-Biosystems ® , UK) or anti-calcitonin receptor (anti-calcitonin receptor precursor antibody; dilution 1:50; Novus Biologicals ® , USA). After rinsing with PBS, the slides were incubated with secondary antibody followed by streptavidin–peroxidase complex both for 30 min at room temperature with a PBS wash between each step (LSAB+ system; DakoCytomation ® , USA). The slides were developed with diaminobenzidine–H 2 O 2 (DAB+ system; DakoCytomation ® , USA), counterstained with Harry’s haematoxylin and mounted. Thyroid tissue for CTR and tonsil tissue for GR were used as positive controls. Controls of primary antibody specificity included the omission or substitution of primary antiserum with normal bovine serum.
The immunohistochemical staining was assessed using a direct light microscope, accordingly to the site of stain of each antibody (GR, nuclei; CTR, nuclei and cytoplasm). A differential count was performed for MSCs and MGCs. Staining was quantified through manual counting of at least 1000 MSCs in 10 different fields at a magnification of 400×. In the same 10 high-power fields, all MGCs were counted to a maximum of 1000 cells. The labelling index (LI) was expressed as the percentage of positive cells with nuclear staining for CTR in each section. The H -score ( H ) takes into account the intensity of the cytoplasmic CTR staining and nuclear GR staining expressed in values ranging from 0 to 3+ (0, no stain; 1+, weak; 2+, moderate; 3+, strong) in accordance with the methods described by McCarty et al.
The data were analysed using the SPSS 13.0 (SPSS Inc., Chicago, IL, USA) statistical package. The results were expressed as the mean. To compare the marker H -score with respect to clinical presentation and treatment result groups, the nonparametric Mann–Whitney U -test was used. Significance was established at a p value ≤0.05.