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Background Central giant cell granuloma (CGCG) presents as a locally invasive, intraosseous lesion characterized by the accumulation of multinucleated giant cells amidst a matrix of hemorrhage and reactive fibrous tissue that infiltrates bone trabeculae. This idiopathic non-neoplastic proliferative lesion primarily affects the mandible, typically presenting as either unilocular or multilocular radiolucencies on X-rays. Although trauma or intraosseous hemorrhages are potential triggers, the precise histogenesis and etiology remain unclear. CGCG predominantly occurs in children and young adults, with a slight female predilection. Methods and materials A retrospective analysis of 21 cases of CGCG diagnosed at the Oral Pathology/Pathology department of Temple University Hospital between 2015 and 2022 was conducted. Each case was evaluated based on various parameters, including age, gender, presenting symptoms, radiographic findings, clinical differential diagnosis, and histological confirmation. The primary radiographic technique employed for diagnosis was X-ray imaging of the mandible and maxilla. The histological examination involved cutting paraffin-embedded tissue into 5-micrometer-thick sections, which were then stained using routine hematoxylin and eosin (H&E) stain. Notably, no specialized histochemical or immunohistochemical stains were utilized in the evaluation process. Results In our study, we reviewed 21 cases; 9 were male, 11 were female, and one had no available gender data. The age range was 15-76 years, with a mean of 50 years. The mandible was the most commonly affected location (17 cases; 81%) while the maxilla was less commonly involved (4 cases; 19%). Many CGCG lesions were asymptomatic (13 cases; 62%); eight cases (38%) were symptomatic, with pain and fullness of the affected dental region being the main manifestations. In a few cases, conditions such as brown tumor (severe hyperparathyroidism) and odontogenic neoplasms, such as ameloblastoma, were suspected clinically and radiographically. The diagnosis of CGCG with associated acute and chronic inflammation was confirmed in all the cases. Histological evaluation of routinely stained slides was the main diagnostic tool utilized. No special stains or molecular studies were required to establish the final diagnosis. Conclusions Our investigation has determined that CGCG exhibits a non-neoplastic nature, displaying a spectrum of behaviors ranging from non-aggressive to aggressive tendencies. While CGCG is predominantly observed in the mandible, rare instances of involvement in the maxilla have also been documented. Importantly, no confirmed association with neoplastic lesions was identified during our analysis. The clinical course of CGCG tends to be indolent, with some cases presenting in association with impacted teeth. It's noteworthy that CGCG can present features mimicking neoplastic conditions, such as ameloblastoma, or localized lesions linked to systemic disorders such as hyperparathyroidism (brown tumor).
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SHP1, a tyrosine phosphatase, negatively regulates B-cell receptor (BCR) signaling. Ibrutinib selectively inhibits BTK and has been approved for the treatment of several types of B-cell lymphomas, but not yet in diffuse large B-cell lymphoma (DLBCL). A phase 3 clinical trial of ibrutinib-containing regimen has been completed to evaluate its activity in subtypes or subsets of DLBCL patients. Although the subtype of activated B-cell like (ABC) DLBCL is characterized by chronic active BCR signaling, only a fraction of ABC-DLBCL patients seem to benefit from ibrutinib-containing regimen. New alternative predictive biomarkers are needed to identify patients who better respond. We investigated if SHP1 plays a role in defining the level of the BCR activity and impacts the response to ibrutinib. A meta-analysis revealed that lack of SHP1 protein expression as well as SHP1 promoter hypermethylation is strongly associated with NHL including DLBCL. On a tissue microarray of 95 DLBCL samples, no substantial difference in SHP1 expression was found between the GCB and non-GCB subtypes of DLBCL. However, we identified a strong reverse correlation between SHP1 expression and promoter methylation suggesting that promoter hypermethylation is responsible for SHP1 loss. SHP1 knockout in BCR-dependent GCB and ABC cell lines increased BCR signaling activities and sensitize lymphoma cells to the action of ibrutinib. Rescue of SHP1 in the knockout clones, on the other hand, restored BCR signaling and ibrutinib resistance. Further, pharmacological inhibition of SHP1 in both cell lines and patient-derived primary cells demonstrate that SHP1 inhibition synergized with ibrutinib in suppressing tumor cell growth. Thus, SHP1 loss may serve as an alternative biomarker to cell-of-origin to identify patients who potentially benefit from ibrutinib treatment. Our results further suggest that reducing SHP1 pharmacologically may represent a new strategy to augment tumor response to BCR-directed therapies. Schematic diagram summarizing the major findings. Left panel. When SHP1 is present and functional, it negatively regulates the activity of the BCR pathway. Right pane. When SHP1 is diminished or lost, cells depend more on the increased BCR signaling and making them vulnerable to BTK inhibitor, ibrutinib. Diagram was generated using BioRender.