Report of Four Cases with High-Grade Surface Osteosarcoma

Advances in drug resistance of osteosarcoma caused by pregnane X receptor

Osteosarcoma (OS) is a prevalent malignancy among adolescents, commonly manifesting during childhood and adolescence. It exhibits a high degree of malignancy, propensity for metastasis, rapid progression, and poses challenges in clinical management. Chemotherapy represents an efficacious therapeutic modality for OS treatment. However, chemotherapy resistance of OS is a major problem in clinical treatment. In order to treat OS effectively, it is particularly important to explore the mechanism of chemotherapy resistance in OS.The Pregnane X receptor (PXR) is a nuclear receptor primarily involved in the metabolism, transport, and elimination of xenobiotics, including chemotherapeutic agents. PXR involves three stages of drug metabolism: stage I: drug metabolism enzymes; stage II: drug binding enzyme; stage III: drug transporter.PXR has been confirmed to be involved in the process of chemotherapy resistance in malignant tumors. The expression of PXR is increased in OS, which may be related to drug resistance of OS. Therefore, wereviewed in detail the role of PXR in chemotherapy drug resistance in OS.

Surface bone sarcomas: an update on current clinicopathological diagnosis and treatment

Surface bone sarcomas are rare malignant bone tumours. Osseous and cartilaginous surface bone sarcomas are the most common, with parosteal and periosteal osteosarcomas, periosteal chondrosarcomas and secondary peripheral chondrosarcomas being the most frequent.

Their clinical symptoms are non-specific and include pain for several months, swelling and limited range of motion of the adjacent joints.

Prompt diagnosis is important, as biological behaviour, imaging and histopathologic characteristics, treatment and prognosis differ considerably from their conventional intramedullary counterparts. Moreover, their imaging characteristics are not infrequently non-characteristic and may be misinterpreted as juxtacortical benign lesions leading to incorrect diagnosis and treatment, with life-threatening repercussions. Molecular studies and histopathological sampling are essential for accurate diagnosis.

There are still numerous issues regarding the biology, pathophysiology and treatment options of these entities due to their rarity.

Cite this article: EFORT Open Rev 2021;6:905-917. DOI: 10.1302/2058-5241.6.210064

A review of imaging of surface sarcomas of bone

Surface lesions of bone are uncommon. Although their imaging features generally mirror those of their intramedullary counterparts, surface lesions may demonstrate distinct characteristics which along with their unusual location present a diagnostic challenge. Surface sarcomas are usually of a lower grade compared with intramedullary variants, leading to differences in management. Osteosarcoma arising from the cortical surface of the bone is termed juxtacortical or surface osteosarcoma and includes three distinct entities: parosteal, periosteal, and high-grade surface osteosarcoma. We also review the features intracortical osteosarcoma, which some authors include under the umbrella term surface osteosarcoma. These lesions exhibit biologic features distinct from those of conventional intramedullary osteosarcoma, which underlines the importance of accurate imaging diagnosis. Periosteal chondrosarcoma and periosteal Ewing sarcoma also have distinctive imaging appearances. The purpose of this article is to review surface sarcomas of bone with regard to their clinical and radiological features and to discuss the differential diagnosis for each condition.

High-Grade Surface Osteosarcoma: Clinical Features and Oncologic Outcome

Background

High-grade surface osteosarcoma is an extremely rare subtype of osteosarcoma. The treatment outcome for this tumor varies in different centers.

Methods

This was a retrospective study of high-grade surface osteosarcoma; clinical, radiological, and histological materials were reviewed.

Results

We studied 23 patients (16 males, seven females); median age was 24 years old. All the tumors involved the lower limb, located at the diaphysis in 11 patients and at the metaphysis in 12 patients. Even though the majority of tumors were located at the surface of the bone, the medullary canal was involved in 10 patients. The microscopic findings were indistinguishable from conventional central osteosarcoma. All the patients were treated with a combination of surgery and systemic chemotherapy. Follow-up data were completed in 20 patients; follow-up duration ranged from 27 months to 182 months or until the patient died of the disease (5–104 months). Of the 20 patients, 12 died of the disease, and eight patients were alive at the time of the last follow-up. The 5-year overall survival rate was 37.6%.

Conclusions

Our study revealed that the treatment outcome for this tumor shows a poor survival rate.

Osteosarcoma in Adult Patients Living with HIV/AIDS

Background. HIV infection has reached epidemic proportions in South Africa, with an estimated prevalence of 21.5% in adults living in the province of KwaZulu-Natal. Several malignancies have been identified as part of the spectrum of immunosuppression-related manifestations of HIV infection. Very few reports, however, exist regarding the occurrence of non-AIDS-defining sarcomas in the extremities or limb girdles. Methods. A retrospective review was performed on all adult patients, between the ages of 30 and 60 years, with histologically confirmed osteosarcomas of the appendicular skeleton referred to a tertiary-level orthopaedic oncology unit. Results. Five out of the nine patients (62.5%) included in the study were found to be HIV positive. The average CD4 count of these patients was 278 (237-301) cells/mm(3), indicating advanced immunological compromise. Three of the malignancies in HIV-positive patients occurred in preexisting benign or low-grade tumours. Conclusion. A heightened index of suspicion is required in HIV patients presenting with unexplained bone and joint pain or swelling. Judicious use of appropriate radiological investigation, including magnetic resonance imaging of suspicious lesions and timely referral to an appropriate specialized orthopaedic oncology unit, is recommended.

Taurine chloramine induces apoptosis in human osteosarcoma cell lines

Although combination of surgery with chemotherapy has noticeably improved the survival rate of osteosarcoma patients, the application of anticancer drugs is still associated with significant adverse reactions, for instance acquisition of drug-resistant phenotypes, necessitating the development of new chemotherapeutical agents. Therefore, the aim of this study was to research, if taurine chloramine (NCT) induces apoptosis in the osteosarcoma cell lines HOS, MG-63, and SAOS-2. Proliferation of osteosarcoma cells was detected with the "EZ4U Cell Proliferation and Cyotoxicity Assay" showing a time- and dose-dependent cytotoxic effect of NCT on these cell lines. After 3 h of incubation all cell lines showed significantly less cells at 5.5 mM NCT solutions, after 6 h at concentrations of 1.1 and 2.2 mM. Acridine-orange fluorescence nuclear staining showed characteristic features of apoptosis. DNA fragmentation was detected via ELISA, showing significant results for HOS and MG-63 after 6 h at an NCT concentration of 3.3 mM. Results of JC-1 mitochondrial FACS analysis presented a significant increase in apoptotic cells after 6 h at 3.3 mM for the tested cell lines. Summarized, the results of this study indicate that NCT is a promising agent in osteosarcoma therapy.