Chronic epilepsy may cause important bipolar bony lesions. We aim to compare the specific pathoanatomic metrics of the bony lesions in chronic shoulder anterior instability that occur in the epileptic population vs non-epileptic population.
METHODS: From 2006 to 2020, we included epileptic and non-epileptic patients with anterior recurrent shoulder instability. We randomly adjusted the patients of the two groups according to the sex, age and type of management. We included 50 patients. For each included patient, we performed an in-depth CT-scan analysis and comparison of the glenoid bone loss: PICO method using the best-fit circle; and the Hill-Sachs lesion: the depth and width were given as a percentage of the humeral head diameter on an axial view. We also evaluated the engaging character of the involved lesion using the On-track/Off-track analysis. Those characteristics were compared between the two groups.
RESULTS: We found a glenoid bone loss in 32 patients. Glenoid bone loss was not significantly greater in patients with epilepsy (p=0.052). A Hill-Sachs lesion was found in 42 patients (22 in epileptic group and 20 in non-epileptic group). Hill-Sachs lesions were significantly deeper and larger in the epileptic group. (depth: 22% vs 9%, p<0.001; width: 43% vs 28%, p=0.003). In the epileptic group 90% of the bone lesions were OFF-track versus 30% in the non-epileptic group. Thus, the epileptic patients presented more engaging bony lesions than non-epileptic patients (p=0.001) (OR=23).
CONCLUSIONS: In a population of epileptic patients, Hill-Sachs lesions are larger and deeper than in patients with non- epileptic shoulder instability. By contrast, there is no significant difference regarding the characteristics of the glenoid bone loss if present. This implies that bone lesions in instable shoulders of epileptic patients need at least a bony stabilization procedure on the humeral side in the majority of cases.

BACKGROUND: Leukocyte Ig-like receptor B family 4 (LILRB4) as an immune checkpoint on myeloid cells is a potential target for tumor therapy. Extensive osteolytic bone lesion is the most characteristic feature of multiple myeloma. It is unclear whether ectopic LILRB4 on multiple myeloma regulates bone lesion.
METHODS: The conditioned medium (CM) from LILRB4-WT and -KO cells was used to analyze the effects of LILRB4 on osteoclasts and osteoblasts. Xenograft, syngeneic and patient derived xenograft models were constructed, and micro-CT, H&E staining were used to observe the bone lesion. RNA-seq, cytokine array, qPCR, the activity of luciferase, Co-IP and western blotting were used to clarify the mechanism by which LILRB4 mediated bone damage in multiple myeloma.
RESULTS: We comprehensively analyzed the expression of LILRB4 in various tumor tissue arrays, and found that LILRB4 was highly expressed in multiple myeloma samples. The patient\'s imaging data showed that the higher the expression level of LILRB4, the more serious the bone lesion in patients with multiple myeloma. The conditioned medium from LILRB4-WT not -KO cells could significantly promote the differentiation and maturation of osteoclasts. Xenograft, syngeneic and patient derived xenograft models furtherly confirmed that LILRB4 could mediate bone lesion of multiple myeloma. Next, cytokine array was performed to identify the differentially expressed cytokines, and RELT was identified and regulated by LILRB4. The overexpression or exogenous RELT could regenerate the bone damage in LILRB4-KO cells in vitro and in vivo. The deletion of LILRB4, anti-LILRB4 alone or in combination with bortezomib could significantly delay the progression of bone lesion of multiple myeloma.
CONCLUSIONS: Our findings indicated that LILRB4 promoted the bone lesion by promoting the differentiation and mature of osteoclasts through secreting RELT, and blocking LILRB4 singling pathway could inhibit the bone lesion.

Brown tumors (also known as osteitis fibrosa cystica) are rare complications of end-stage renal disease (ESRD) and secondary hyperparathyroidism (HPT), characterized by focal bone lesions that resemble neoplasms. They are often misdiagnosed as metastatic bone disease, especially in patients with a history of malignancy. We present a case of a 60-year-old man with a history of renal cell carcinoma (RCC), and ESRD on hemodialysis (HD), who developed diffuse bone lesions on imaging with osteolytic/osteoblastic appearance concerning metastases, but on further workup was found to have brown tumors. We discuss the treatment and outcome and briefly review the relevant medical literature.

Tumors that develop on the chest wall are usually rare. This case report highlights a rare occurrence of a giant cell tumor originating from the anterior arch of the fourth rib. The patient, a 21-year-old male, presented with a bulging mass that had been gradually increasing in size over an eight-month period, reaching dimensions of 12 x 8 cm. Despite the noticeable swelling, the patient reported no associated pain or discomfort and denied any history of weight loss or trauma. The absence of chest pain or cardiovascular symptoms distinguished this case from other chest wall pathologies. This report underscores the importance of considering rare entities such as giant cell tumors in the differential diagnosis of chest wall masses, especially in cases where clinical presentation and patient history do not align with more common conditions.

Multiple myeloma (MM) is a blood cancer caused by uncontrolled growth of clonal plasmacells. Bone disease is responsible for the severe complications of MM and is caused by myeloma cells infiltrating the bone marrow and inducing osteoclast activation. To date, no treatment for MM is truly curative since patients relapse and become refractory to all drug classes. Cannabinoids are already used as palliative in cancer patients. Furthermore, their proper anticancer effect was demonstrated in many cancer models in vitro, in vivo, and in clinical trials. Anyway, few information was reported on the effect of cannabinoids on MM and no data has been provided on minor phytocannabinoids such as cannabigerol (CBG), cannabichromene (CBC), cannabinol (CBN), and cannabidivarin (CBDV). Scientific literature also reported cannabinoids beneficial effect against bone disease. Here, we examined the cytotoxic activity of CBG, CBC, CBN, and CBDV in vitro in MM cell lines, their effect in modulating MM cells invasion toward bone cells and the bone resorption. Subsequently, according to the in vitro results, we selected CBN for in vivo study in a MM xenograft mice model. Results showed that the phytocannabinoids inhibited MM cell growth and induced necrotic cell death. Moreover, the phytocannabinoids reduced the invasion of MM cells toward osteoblast cells and bone resorption in vitro. Lastly, CBN reduced in vivo tumor mass. Together, our results suggest that CBG, CBC, CBN, and CBDV can be promising anticancer agents for MM.

Fibrous dysplasia (FD) is a rare bone disorder characterized by the replacement of normal bone with benign fibro-osseous tissue. Developments in our understanding of the pathophysiology and treatment options are impeded by the lack of suitable research models. In this study, we developed an in vitro organotypic model capable of recapitulating key intrinsic and phenotypic properties of FD. Initially, transcriptomic profiling of individual cells isolated from patient lesional tissues unveiled intralesional molecular and cellular heterogeneity. Leveraging these insights, we established patient-derived organoids (PDOs) using primary cells obtained from patient FD lesions. Evaluation of PDOs demonstrated preservation of fibrosis-associated constituent cell types and transcriptional signatures observed in FD lesions. Additionally, PDOs retained distinct constellations of genomic and metabolic alterations characteristic of FD. Histological evaluation further corroborated the fidelity of PDOs in recapitulating important phenotypic features of FD that underscore their pathophysiological relevance. Our findings represent meaningful progress in the field, as they open up the possibility for in vitro modeling of rare bone lesions in a three-dimensional context and may signify the first step towards creating a personalized platform for research and therapeutic studies.

Bone lesions in sarcoidosis are more common than previously known. A 59-year-old female with a history of sarcoidosis was referred due to suspected lung cancer. 18F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) revealed numerous bone lesions in addition to abnormal uptake by pulmonary nodules and mediastinal lymph nodes, which mimicked metastatic advanced lung cancer. Biopsy of bone lesions detected epithelioid cell granuloma consistent with bone sarcoidosis. Moreover, prednisolone treatment was tried to exclude malignant disease. One month after prednisolone administration, bone lesions and other abnormal uptake disappeared on PET/CT. Bone sarcoidosis is often asymptomatic and is discovered incidentally as multiple lesions that may require differentiation from malignant disease. Biopsy of bone lesions and administration of corticosteroids may be useful for accurate diagnosis.

Langerhans cell histiocytosis (LCH) is a rare disease with limited treatment options. We present a case involving a 57-year-old woman afflicted with an isolated LCH bone osteolytic lesion. A single bisphosphonate infusion significantly alleviated pain, and follow-up scans via CT, PET-CT, and MRI revealed a substantial recalcification of the lesion. Conducting an extensive literature review, we identified 46 cases documenting the efficacy of bisphosphonates in the context of LCH. These findings have raised interest in bisphosphonate infusion as a simple therapeutic alternative in similar situations, with benefits in terms of bone recalcification and pain control for individuals with LCH.

OBJECTIVE: Fibrous dysplasia (FD) is a rare genetic disease with benign bone tumors. FD can affect one (monostotic FD) or multiple bones (polyostotic FD), with craniofacial lesions being common. Because of its rarity, there are only few clinical reports on FD in the head and neck region and its clinical characteristics remain incompletely defined. This study aimed to determine patient demographics, symptoms, diagnostics, and given treatment in patients with FD of the head and neck in a Finnish population.
METHODS: A retrospective review on all patients diagnosed with or treated for FD of the head and neck at the Helsinki University Hospital during 2005-2020.
RESULTS: In total 74 patients were identified; 54% were male and the mean age 45 years. Overall 95% had monostotic FD. Mandibula and maxilla were the most common anatomic sites. Majority of patients had symptoms, most commonly pain and lesion growth, and 49% had extra-skeletal symptoms. For all, diagnosis was primarily based on imaging findings, biopsies were obtained from 41%. Altogether 54 patients (73%) were managed by observation only, 20 patients (27%) received treatment; ten bisphosphonates, six surgery and four both.
CONCLUSIONS: Although highly variable in its clinical manifestations, head and neck FD lesions are often symptomatic and impose risk for extra-skeletal complications. Treatment is often conservative but should be individually tailored. Future studies are encouraged to better define the disease characteristics and hopefully offer new treatment possibilities.

OBJECTIVE: To determine if macroscopic intralesional fat detected in bone lesions on CT by Hounsfield unit (HU) measurement and on MRI by macroscopic assessment excludes malignancy.
METHODS: All consecutive CT-guided core needle biopsies (CNB) of non-spinal bone lesions performed at a tertiary center between December 2005 and September 2021 were reviewed. Demographic and histopathology data were recorded. All cases with malignant histopathology were selected, and imaging studies were reviewed. Two independent readers performed CT HU measurements on all bone lesions using a circular region of interest (ROI) to quantitate intralesional fat density (mean HU < -30). MRI images were reviewed to qualitatively assess for macroscopic intralesional fat signal in a subset of patients. Inter-reader agreement was assessed with Cronbach\'s alpha and intraclass correlation coefficient.
RESULTS: In 613 patients (mean age 62.9 years (range 19-95 years), 47.6% female), CT scans from the CNB of 613 malignant bone lesions were reviewed, and 212 cases had additional MRI images. Only 3 cases (0.5%) demonstrated macroscopic intralesional fat on either CT or MRI. One case demonstrated macroscopic intralesional fat density on CT in a case of metastatic prostate cancer. Two cases demonstrated macroscopic intralesional fat signal on MRI in cases of chondrosarcoma and osteosarcoma. Inter-reader agreement was excellent (Cronbach\'s alpha, 0.95-0.98; intraclass correlation coefficient, 0.90-0.97).
CONCLUSIONS: Malignant lesions rarely contain macroscopic intralesional fat on CT or MRI. While CT is effective in detecting macroscopic intralesional fat in primarily lytic lesions, MRI may be better for the assessment of heterogenous and infiltrative lesions with mixed lytic and sclerotic components.
CONCLUSIONS: Macroscopic intralesional fat is rarely seen in malignant bone tumors and its presence can help to guide the diagnostic workup of bone lesions.
CONCLUSIONS: • Presence of macroscopic intralesional fat in bone lesions has been widely theorized as a sign of benignity, but there is limited supporting evidence in the literature. • CT and MRI are effective in evaluating for macroscopic intralesional fat in malignant bone lesions with excellent inter-reader agreement. • Macroscopic intralesional fat is rarely seen in malignant bone lesions.