A serologic survey using a highly sensitive enzyme-linked immunosorbent assay confirmed the anticipated finding of naturally acquired antibodies to tetanus toxin both in humans and animals on the Galápagos Islands. In 57 inhabitants (mean age, 31.3 years) who had not been vaccinated against tetanus, antibody to tetanus toxin was detected in the blood in varying titers (geometric mean [reciprocal] titer [GMT], 0.015 international units [IU]/ml). In one individual the titer of antibody was greater than 12.5 IU/ml. Two individuals who had never been vaccinated against tetanus but who had reported having had clinical tetanus had titers of antibody to tetanus toxin of 0.02 IU/ml and 0.3 IU/ml, respectively. All nine of the animals studied showed antibody to tetanus toxin (GMT, 0.028 IU/ml).

Background Bone tumors are not a frequent occurrence and bone-infarct-associated sarcomas are even rarer. The prognosis of this disease is poor and its treatment remains a challenge. Nevertheless, hardly any analyses in literature report on secondary osteosarcoma (SO) on bone infarct and most of the data available do not provide sufficient details. We evaluated whether this condition could be further characterized and if prognosis could be influenced by the chemotherapy treatment. In particular, we sought to determine (1) the main features of this rare disease; (2) the overall survival (OS) rate; (3) the OS rate associated to chemotherapy treatment; (4) the correspondence between our results and published data in terms of survival. Methods We retrospectively reviewed patients admitted at Rizzoli Orthopedic Institute of Bologna between 1992 and 2018 (1465 total cases of osteosarcoma). We identified a list of 11 cases of SO on bone infarct (cohort 1). We conferred about the epidemiology, surgical and chemotherapy (ChT) treatment and surveillance of infarct-associated osteosarcoma showing the correlation to data present in literature, corresponding to 15 case reports published within 1962-2018 (cohort 2). Results (1) cohort 1 was made of 11 patients: six females and five males, median age was 55 years. Nine (81%) were grade 4, two (19%) grade 3. Tumor predominantly arise on distal femur (64%). Most of patients had localized osteosarcoma at the diagnosis (81%); resection surgery was the elective treatment (73%) followed by amputation (18%). Of 11 patients, seven received also ChT (64%). (2) Five-years OS was 62% (95% CI: 28-84). Median OS was 74 months (95% CI: 12-not reached). The cumulative incidence of cancer-related deaths (CICRD) was 37.7% (95% CI: 11.4-64.5) at 120 months. (3) In the group treated with only surgery OS was 50% at 5 years. For patients treated with any form of ChT, OS was 71% at 5 years (p=0.4773) and hazard ratio (HR) 0.56. The CICRD was 29% (at 2 years of follow-up. Instead, it was of 50% for patients treated only with surgery. (4) Median survival was 74 months and 19 months for cohort 1 and cohort 2 respectively (p=0.09). Data analysis showed a decreased HR for cohort 1 compared to cohort 2 (HR 0.378). Results confirmed also stratifying for age and ChT administration (HR 0.355). Conclusions Based on this work, our opinion is that the choice to undergo the patients to ChT combined to surgery could improve their prognosis.

Chondroblastoma is a rare benign chondrogenic tumor that occurs in skeletally immature patients between ages 10 and 20 years old. In literature are reported few cases of lung metastases, mainly occurred after surgery or local recurrences. There is no evidence on the pathogenesis of lung metastasis, as well as pulmonary disease course. Few treatments for metastases with aggressive behavior were based on chemotherapy regimen employed in other sarcoma with no results or not satisfying ones. Denosumab is approved for treatment of giant cell tumors and it is under investigation for other giant cell-rich bone tumors. Here, we report a case of a 16-year-old male chondroblastoma of the left humerus with bilateral lung metastases at presentation and progressing during follow-up, treated with denosumab for almost 2 years. We confirm that denosumab treatment can be effective in controlling chondroblastoma metastasis and it has been a safe procedure in an adolescent patient.

AimsThe preoperative grading of chondrosarcomas of bone that accurately predicts surgical management is difficult for surgeons, radiologists, and pathologists. There are often discrepancies in grade between the initial biopsy and the final histology. Recent advances in the use of imaging methods have shown promise in the ability to predict the final grade. The most important clinical distinction is between grade 1 chondrosarcomas, which are amenable to curettage, and resection-grade chondrosarcomas (grade 2 and 3) which require en bloc resection. The aim of this study was to evaluate the use of a Radiological Aggressiveness Score (RAS) to predict the grade of primary chondrosarcomas in long bones and thus to guide management.MethodsA total of 113 patients with a primary chondrosarcoma of a long bone presenting between January 2001 and December 2021 were identified on retrospective review of a single oncology centre’s prospectively collected database. The nine-parameter RAS included variables from radiographs and MRI scans. The best cut-off of parameters to predict the final grade of chondrosarcoma after resection was determined using a receiver operating characteristic curve (ROC), and this was correlated with the biopsy grade.ResultsA RAS of ≥ four parameters was 97.9% sensitive and 90.5% specific in predicting resection-grade chondrosarcoma based on a ROC cut-off derived using the Youden index. Cronbach’s α of 0.897 was derived as the interclass correlation for scoring the lesions by four blinded reviewers who were surgeons. Concordance between resection-grade lesions predicted from the RAS and ROC cut-off with the final grade after resection was 96.46%. Concordance between the biopsy grade and the final grade was 63.8%. However, when the patients were analyzed based on surgical management, the initial biopsy was able to differentiate low-grade from resection-grade chondrosarcomas in 82.9% of biopsies.ConclusionThese findings suggest that the RAS is an accurate method for guiding the surgical management of patients with these tumours, particularly when the initial biopsy results are discordant with the clinical presentation.Cite this article: Bone Joint J 2023;105-B(7):808–814.