Aneurysmal bone cyst is a rare osteolytic lesion of uncertain etiology, commonly observed in the lower limbs, with only 1-2% of reports in gnathic bones. We present the case of a 27-year-old male patient referred to the oral and maxillofacial surgery and traumatology service due to complaints of paresthesia in the mental region and increased mandibular volume. Physical examination revealed midline shift and hard consistency. Imaging examinations demonstrated a radiolucent/hypodense lesion with disruption of the mandibular cortices. The histopathological examination of incisional biopsy material led to the diagnosis of a central giant cell lesion. The patient underwent surgical resection, and the histopathological analysis of the specimen revealed a predominantly solid lesion, characterized by blood-filled spaces of varying size, not covered by epithelium or endothelium, with the presence of spindle cells, multinucleated giant cells, and basophilic osteoid material, concluding the diagnosis of mixed-type aneurysmal bone cyst. Despite being uncommon, aneurysmal bone cysts should be considered in the differential diagnosis of volumetric increase in the gnathic bones of young patients.

Sporadic giant cell granulomas (GCGs) of the jaws and cherubism-associated giant cell lesions share histopathological features and microscopic diagnosis alone can be challenging. Additionally, GCG can morphologically closely resemble other giant cell-rich lesions, including non-ossifying fibroma (NOF), aneurysmal bone cyst (ABC), giant cell tumour of bone (GCTB), and chondroblastoma. The epigenetic basis of these giant cell-rich tumours is unclear and DNA methylation profiling has been shown to be clinically useful for the diagnosis of other tumour types. Therefore, we aimed to assess the DNA methylation profile of central and peripheral sporadic GCG and cherubism to test whether DNA methylation patterns can help to distinguish them. Additionally, we compared the DNA methylation profile of these lesions with those of other giant cell-rich mimics to investigate if the microscopic similarities extend to the epigenetic level. DNA methylation analysis was performed for central (n = 10) and peripheral (n = 10) GCG, cherubism (n = 6), NOF (n = 10), ABC (n = 16), GCTB (n = 9), and chondroblastoma (n = 10) using the Infinium Human Methylation EPIC Chip. Central and peripheral sporadic GCG and cherubism share a related DNA methylation pattern, with those of peripheral GCG and cherubism appearing slightly distinct, while central GCG shows overlap with both of the former. NOF, ABC, GCTB, and chondroblastoma, on the other hand, have distinct methylation patterns. The global and enhancer-associated CpG DNA methylation values showed a similar distribution pattern among central and peripheral GCG and cherubism, with cherubism showing the lowest and peripheral GCG having the highest median values. By contrast, promoter regions showed a different methylation distribution pattern, with cherubism showing the highest median values. In conclusion, DNA methylation profiling is currently not capable of clearly distinguishing sporadic and cherubism-associated giant cell lesions. Conversely, it could discriminate sporadic GCG of the jaws from their giant cell-rich mimics (NOF, ABC, GCTB, and chondroblastoma).

There is a lack of data on post-HSCT non-osteopenic bone pathology specifically for children with inborn errors of immunity (IEI). We collected data on non-osteopenic bone pathology in children with IEI post-HSCT over two decades in a large tertiary pediatric immunology center.
Descriptive study with data analysis of bone pathology in allo-HSCT for IEI was performed between 1/1/2000 to 31/12/2018 including patients alive at follow-up to July 2022. Records were analyzed for bone pathology and risk factors. Exclusion criteria included isolated reduced bone density, fractures, and skeletal anomalies due to underlying IEI and short stature without other bone pathology. Bone pathologies were divided into 5 categories: bone tumors; skeletal dysplasia; avascular necrosis; evolving bone deformities; slipped upper femoral epiphysis.
A total of 429 children received HSCT between 2000 and 2018; 340 are alive at last assessment. Non-osteopenic bone pathology was observed post-HSCT in 9.4% of patients (32/340, mean 7.8 years post-HSCT). Eleven patients (34%) had > 1 category of bone pathology. Seventeen patients (17/32; 53%) presented with bilateral bone pathology. The majority of patients received treosulfan-based conditioning (26/32; 81.2%). Totally, 65.6% (21/32) of patients had a history of prolonged steroid use (> 6 months). Pain was the presenting symptom in 66% of patients, and surgical intervention was required in 43.7%. The highest incidence of bone pathologies was seen in Wiskott-Aldrich syndrome (WAS) (n = 8/34; 23.5%) followed by hemophagocytic lymphohistiocytosis patients (n = 3/16; 18.8%).
Non-osteopenic bone pathology in long-term survivors of allo-HSCT for IEI is not rare. Most patients did not present with complaints until at least 5 years post-HSCT highlighting the need for ongoing bone health assessment for patients with IEI. Children presenting with stunted growth and bone pathology post-HSCT should undergo skeletal survey to rule out development of post-HSCT skeletal dysplasia. Increased rates and complexity of bone pathology were seen amongst patients with Wiskott-Aldrich syndrome.

In this work, we investigated cases of birth of calves with congenital defects in a farm in Southern Brazil. Only calves born from heifers were affected, and the disease occurred in both crossbred and purebred calves. Three necropsies were performed, tissues were collected for histopathology, and samples of liver of calves, blood serum, and food provided for cows and heifers were collected to quantify the levels of the minerals: manganese, copper, and zinc. The calves were born weak, with disproportionate dwarfism, limb deformities, and enlarged joints. Heads were shortened and domed. Long bones had a shortened diaphysis and a normal-sized epiphysis, when compared to the control. In one of the cases, there were white-yellowish lines on the metaphyseal surface of the epiphyseal plate. Histopathology of growth plates revealed premature closure, disarrangement of chondrocyte columns, and collapse of primary spongiosa. These findings supported a diagnosis of chondrodysplasia. Liver manganese levels were under the reference values in the three calves. Food analysis revealed insufficient levels of manganese in the diet of heifers, especially in sorghum silage, which was provided as the main source of food for the category in some periods. Approximately 6 months after the diet was changed, the problem ceased and only normal calves continued to be born. Our findings allowed to conclude the diagnosis of chondrodysplasia of nutritional origin and reinforce the thesis that manganese is the mineral deficient in these cases.

Traumatic myositis ossificans (MO) circumscripta is an uncommon nonhereditary pathophysiological result of muscular trauma that is detected by radiographic imaging three to four weeks following initial trauma. It is responsible for great global morbidity, with symptoms of prolonged pain, diminished flexibility, and stiffness. There is frequently a delay in diagnosis due to the generalized symptoms and varying radiographic presentation. The goal of therapy is to rule out serious complications (such as soft tissue sarcoma) and to restore strength and range of motion (ROM) as soon as possible. Here we detail the case of a 32-year-old male with a delayed diagnosis of MO who presented to the hospital with left lower extremity pain and swelling following a motor vehicle accident (MVA) that occurred one month prior.

Previous studies have demonstrated that the bone targeting agent BT2-peg2 (BT2-minipeg2, 9), when conjugated to vancomycin and delivered systemically by intravenous (IV) or intraperitoneal (IP) injection accumulates in bone to a greater degree than vancomycin alone, but that this accumulation is associated with severe nephrotoxicity. To determine whether this nephrotoxicity could be attributed to BT2-peg2 itself, we used a rat model to assess the distribution and toxicity of BT2-peg2 after IP injection of 11 mg/kg twice daily for 21 days. The results demonstrated that BT2-peg2 accumulates in bone but there was no evidence of nephrotoxicity or any histopathological abnormalities in the bone. This suggests the nephrotoxicity observed in previous studies is likely due to the altered pharmacokinetics of vancomycin when conjugated to BT2-peg2 rather than to BT2-peg2 itself. Thus, BT2-peg2 may be a safe carrier for the enhanced delivery of antibiotics other than vancomycin to the bone as a means of combating bone infection. However, the data also emphasizes the need to carefully examine the pharmacokinetic characteristics of any BT2-peg2-antibiotic conjugate utilized for treatment of bone infections.

Bone disorders are among the most uncommon causes of stroke, but they should be considered as stroke cause in particular clinical scenarios. On the other hand, osteoporosis/osteopenia and increased fracture risk are well documented post stroke complications. The relationship between stroke and bone health is complex. The current facts suggest that these two conditions share same risk factors, but also are risk factors for each other. However, the evidence shows more clear effect of stroke on the bone health, than in the opposite direction. This extensive review is aiming to fill the huge gap of evidence about this topic, and since bone pathology is extremely rare cause of cerebrovascular accident, although a complex connection between these two conditions definitely exists.

The purpose of this review was to integrate the clinical, radiological, microscopic, and molecular data of published cherubism cases, in addition to therapeutic approaches, to provide more concise information about the disease. An electronic search was undertaken in September 2019. Eligibility criteria included publications having enough clinical, radiological, and histological information to confirm the diagnosis. A total of 260 publications reporting 513 cherubism cases were included. Familial history was observed in 310/458 cases (67.7%). SH3BP2 mutations were reported in 101/108 cases (93.5%) and mainly occurred at protein residues 415, 418, 419, and 420. Retrospective clinical grading was possible in 175 cases. Advanced clinical grading was associated with tooth agenesis, but not with other clinical, radiological, and genetic features. Specific amino acid substitutions of SH3BP2 mutations were not associated with the clinical grading of the disease. \'Wait and see\' was the most common therapeutic approach. In a small number of cases, drugs were used in the treatment, with variable response. In conclusion, there is no clear correlation between the genotype and the phenotype of the disease, but additional genomic and gene expression regulation information is necessary for a better understanding of cherubism.

Dense bone islands (DBIs) are usually asymptomatic and do not require any treatment. This case report presents a DBI of an unusual presentation, which was an incidental finding on a radiograph of a 15-year-old orthodontic patient. The DBI lesion was 24 mm in size, occupying at least 50% of the alveolar process between the upper right canine and lateral incisor, extending up the lateral aspect of the anterior margin of the right nasal fossa. Generally, DBIs are 2-3 mm in size and more commonly found in the mandible in the molar and premolar region. This article further discusses the impact of DBIs on orthodontic treatment such as difficulty with achieving space closure and adequate root tip or torque. We also examine the potential medical implications of DBIs. This is clinically important, especially if multiple DBIs, or osteomas which have a similar radiographic appearance to DBIs, are found in a patient as they may be associated with adenomatous intestinal polyps, which, if not treated, have a 100% chance of becoming malignant transformation.

Osteocytes are the main sensitive and responsive cells for mechanical stimuli in bone. The connexin family enables them to communicate with each other via forming functional gap junctions. However, how osteoporosis-impaired extracellular mechanical property modulates gap junction intercellular communication in osteocytes remains elusive. In this study, we established an ovariectomy (OVX)-induced osteoporosis mouse model in vivo and a polydimethylsiloxane (PDMS)-based cell culture substrate model in vitro to explore the influence of extracellular matrix (ECM) stiffness on cell-to-cell communication in osteocytes. Firstly, we established an OVX-induced osteoporosis mouse model by characterizing the changes in radiography, morphology and histochemistry of femurs. Our results showed that osteoporosis decreased the bone matrix stiffness together with the changes including the loss of osteocytes and the decrease of protein markers. Meanwhile, the dendritic process interconnection and channel-forming protein, Cx43, were reduced in osteoporosis mice. Next we mimicked ECM stiffness changes in vitro by using PDMS substrates at ratios 1:5 for normal stiffness and 1:45 for osteoporosis stiffness. Our results showed that the decreased ECM stiffness reduced the number of dendritic processes in a single cell and gap junctions between adjacent osteocytes. We further detected the decreased expression of Cx43, in the substrate with decreased stiffness. Finally, we found that gap junction-based intercellular communication was reduced in living osteocytes in the substrate with decreased stiffness. This study demonstrates the correlation between ECM mechanical property and cell-to-cell communication in osteocytes and might pave the way for further exploration of osteoporosis in terms of biomechanics.