Aims. Low-grade central osteosarcoma (LGCOS), a rare type of osteosarcoma, often has misleading radiological and pathological features that overlap with those of other bone tumours, thereby complicating diagnosis and treatment. We aimed to analyze the clinical, radiological, and pathological features of patients with LGCOS, with a focus on diagnosis, treatment, and outcomes. Methods. We retrospectively analyzed the medical records of 49 patients with LGCOS (Broder’s grade 1 to 2) treated between January 1985 and December 2017 in a single institute. We examined the presence of malignant features on imaging (periosteal reaction, cortical destruction, soft-tissue invasion), the diagnostic accuracy of biopsy, surgical treatment, and oncological outcome. Results. Based on imaging, 35 of 49 patients (71.4%) exhibited malignant features. Overall, 40 of 49 patients (81.6%) had undergone a biopsy before en-bloc resection: 27 of 40 patients (67.5%) were diagnosed on the first biopsy, which was more accurate when carried out by open rather than needle biopsy (91.3% vs 35.3% diagnostic accuracy, respectively; p < 0.001). Of the 40 patients treated by en-bloc resection, surgical margins were wide in 38 (95.0%) and marginal in two (5.0%). Furthermore, nine of 49 patients (18.4%) underwent curettage (intralesional margin) without previous biopsy. All patients with a positive margin developed local recurrence. Distant metastases occurred in five of 49 patients (10.2%). The mean five-year overall survival (OS) and distant relapse-free survival (D-RFS) were 89.3% (SD 5.1%) and 85.7% (SD 5.5%), respectively. Univariate analysis showed that the occurrence of distant metastasis was a poor prognostic factor for OS (hazard ratio 11.54, 95% confidence interval (CI) 1.92 to 69.17; p < 0.001). Local recurrence was a poor prognostic factor for D-RFS (HR 8.72, 95% CI 1.69 to 45.0; p = 0.002). Conclusion. The diagnosis of LGCOS can be challenging because it may present with non-malignant features and has a low diagnostic accuracy on biopsy. If precisely diagnosed, LGCOS can be successfully treated by surgical excision with wide margins. Cite this article: Bone Joint J 2024;106-B(1):99–106

Aims. Treatment of high-grade limb bone sarcoma that invades a joint requires en bloc extra-articular excision. MRI can demonstrate joint invasion but is frequently inconclusive, and its predictive value is unknown. We evaluated the diagnostic accuracy of direct and indirect radiological signs of intra-articular tumour extension and the performance characteristics of MRI findings of intra-articular tumour extension. Methods. We performed a retrospective case-control study of patients who underwent extra-articular excision for sarcoma of the knee, hip, or shoulder from 1 June 2000 to 1 November 2020. Radiologists blinded to the pathology results evaluated preoperative MRI for three direct signs of joint invasion (capsular disruption, cortical breach, cartilage invasion) and indirect signs (e.g. joint effusion, synovial thickening). The discriminatory ability of MRI to detect intra-articular tumour extension was determined by receiver operating characteristic analysis. Results. Overall, 49 patients underwent extra-articular excision. The area under the curve (AUC) ranged from 0.65 to 0.76 for direct signs of joint invasion, and was 0.83 for all three combined. In all, 26 patients had only one to two direct signs of invasion, representing an equivocal result. In these patients, the AUC was 0.63 for joint effusion and 0.85 for synovial thickening. When direct signs and synovial thickening were combined, the AUC was 0.89. Conclusion. MRI provides excellent discrimination for determining intra-articular tumour extension when multiple direct signs of invasion are present. When MRI results are equivocal, assessment of synovial thickening increases MRI’s discriminatory ability to predict intra-articular joint extension. These results should be interpreted in the context of the study’s limitations. The inclusion of only extra-articular excisions enriched the sample for true positive cases. Direct signs likely varied with tumour histology and location. A larger, prospective study of periarticular bone sarcomas with spatial correlation of histological and radiological findings is needed to validate these results before their adoption in clinical practice. Cite this article: Bone Jt Open 2024;5(10):944–952

Aim. Improving the quality of clinical and radiologic differential diagnosis of intramedullary tumours of long bones. Methods. A database includes clinical and radiologic (X-ray, CT and MRI methods) signs of 106 patients with osteosarcoma (n = 44), chondrosarcoma (n = 31) and giant cell tumour (n = 31). Multivariate analysis of clinical and radiologic characteristics and developing informative set of criteria (decision rule) for the differential diagnosis of osteosarcoma, chondrosarcoma and giant cell tumour were provided with program «ASTA». Results. Before examination in Blokhin Oncology Research Centre in 70% of the osteosarcomas and chondrosarcomas and 60% of GCTs the size of the tumour was more than 8 cm. The reason of the late patients' admission to a specialized medical department is inaccurate diagnosis of these tumours. In our study diagnostic accuracy of the differential diagnosis of osteosarcoma, chondrosarcoma and GCT was 89% in case if the decision rules were based on 14 the most informative clinical and X-ray features, 84% if based on 14 clinical and CT features and 88% if based on 9 MRI features. The comparative analysis revealed a high accuracy in determination of these tumours by using decision rules developed on the basis of multivariate analysis of clinical and X-ray criteria. Conclusion. The comparative accuracy of the developed differential diagnostic criteria (decision rules) of clinical and X-ray, clinical and CT and MRI features proved high informative of each method. The diagnostic accuracy of clinical and X-ray decision rule (89%) exceeded the diagnostic accuracy of radiologist's examination before (62%) and after (83%) admission to Oncology Centre. It proves the necessity for further development and practical application of diagnostic expert systems

Introduction. Tissue diagnosis is essential to direct the definitive management of a suspected soft tissue or bone sarcoma tissue. Knowledge of both the diagnostic yield and accuracy of core needle biopsies is therefore important to give the investigating team information on the likelihood of their initial investigations achieving a diagnosis. Methods. This is a retrospective study of patients referred to a specialist orthopaedic centre for investigation of a suspected soft tissue or bone sarcoma. Details of all core needle biopsies performed in a 13-month period were obtained from the hospital database. We defined a diagnostic biopsy as either a specific tissue diagnosis or a biopsy that decided the definitive management of the patient, specifically if malignancy was excluded and no further intervention was required, to calculate the diagnostic yield. Diagnostic accuracy was established by comparing histological diagnosis at biopsy to that at final excision. Results. The overall diagnostic yield of the biopsies performed was 85% (125 of 148 biopsies) and the diagnostic accuracy was 93% (77 of 83). The diagnostic yield of soft tissue lesions was 93% (79 of 85) and accuracy 98%. For bone lesions the diagnostic yield was 73% (46 of 73) and accuracy was 85%. Discussion. Knowing the diagnostic yield and accuracy of biopsies performed allows the investigating team to give patients and colleagues a figure detailing the likely success of a soft tissue or bone biopsy in being diagnostic. In addition this data provides the investigating team with information on specific biopsy types that are less likely to be diagnostic, such as bone lesions requiring CT guidance. These may benefit from another biopsy method to avoid delay in diagnosis and facilitate timely management

Aims

Intra-articular (IA) tumours around the knee are treated with extra-articular (EA) resection, which is associated with poor functional outcomes. We aim to evaluate the accuracy of MRI in predicting IA involvement around the knee.

Background. The National Institute of Clinical Excellence (NICE) published clinical guidelines in 2006 defining urgent referral criteria for soft tissue sarcoma to help improve the diagnostic accuracy and overall outcome. Despite these guidelines inadvertent excisions of soft tissue sarcomas continue to occur with alarming frequency potentially compromising patient outcomes. Objective. We reviewed the East Midlands Sarcoma Service experience of treating inadvertent excision of STSs and highlight the patient profile, referral pattern, subsequent management and oncological outcome associated with inadvertent resection. Methods. Patients were identified from our sarcoma database and a retrospective case note review performed. Results. Over a period of 32 months, 42 patients presented to our specialist centre after unplanned excision of soft tissue sarcomas. There were 29 men and 13 women, with a mean age at presentation of 59 years (19-90). 50% of the tumours were located in lower extremity, 33% around the trunk and 17% in the upper extremity. The unplanned surgery was most commonly from general surgeons, non-specialist orthopaedic surgeons, general practitioners followed by plastic surgeons. Re-resection was undertaken in 40 (95.2%) cases to achieve clear margins. Residual tumour was present in 74% of cases. Resected specimen histology was high grade in 90% of cases. Limb salvage surgery was not possible in 4 cases. Conclusion. Unplanned excision of sarcoma by non-oncologic surgeons remains a problem. It appears that it is equally prevalent in varied surgical community and general practitioners. Patients with soft tissue masses of unknown identity should be appropriately imaged and if the diagnosis remains unclear be transferred to centres that specialize in treating sarcomas for biopsy and adequate initial resection. Implementation of NICE guidelines and local strategies could improve the expedient management of these patients

We have previously shown that cytological diagnosis based on fine-needle aspiration biopsy (FNAB) is a safe and efficient method for the discrimination between benign, primary malignant and metastatic bony lesions. We have now studied metastatic lesions to assess the diagnostic accuracy and to ascertain whether FNAB allows identification of the primary lesion. Between 1990 and 1997, 447 patients were referred for diagnosis of skeletal lesions of unknown type. Of these 119 proved to have metastatic disease, either myeloma or lymphoma. Nine were excluded leaving 110 consecutive patients with metastatic carcinoma (80), myeloma (16) or lymphoma (14). FNAB gave a correct diagnosis in 102 of the 110 patients (93%). In eight it was inconclusive. It correctly diagnosed 15 of 16 patients with myeloma, 12 of 14 with lymphoma, and 75 of 80 with metastatic carcinoma. Furthermore, the site and type of malignancy were correctly suggested in two-thirds of patients with metastatic carcinoma. Overall, only seven open biopsies were carried out. We conclude that time-consuming and costly investigations can be reduced by choosing FNAB as the initial diagnostic method for skeletal lesions of unknown origin. The choice of radiological examinations, laboratory tests and surgical biopsies can be determined by using FNAB

We evaluated the diagnostic accuracy of fine-needle aspiration biopsy in a prospective study of 300 patients with previously undiagnosed bone lesions. Patients with suspected local recurrence of a primary bone tumour or a metastatic lesion of a previously diagnosed malignancy were excluded. Fine-needle aspiration biopsy was performed under radiological control as an outpatient procedure. The series was grouped into three major categories: 1) benign bone lesions including infections; 2) primary malignant bone tumours; and 3) metastases including lymphomas and myelomas. We compared the cytological diagnosis with the final diagnosis as assessed by histological examination and/or the clinical and radiological features. Material considered conclusive for cytological diagnosis was obtained from 251 of the 300 patients. Of the 49 failures, there were 24 aspirates with insufficient cellular yield and 25 in which a diagnosis could not be made although the cytological material was adequate in quantity. Most of the inconclusive aspirates (36/49) were obtained from benign bone lesions. The diagnosis was correct in 239 (95%) of the 251 cases providing adequate cytological material. There were eight (3%) falsely benign diagnoses, one (0.3%) falsely malignant, and three cases in which we were unable to differentiate between sarcoma and a metastasis. Chondrosarcoma (2/12) gave the greatest diagnostic difficulty and Ewing’s sarcoma the least (0/9). There were no decisive errors of treatment. All falsely benign or malignant diagnoses were questioned, and led to open biopsy since they did not correlate with the clinical and radiological features. Our study suggests that fine-needle aspiration biopsy is a valid option for the diagnosis of bone tumours. It is a simple outpatient procedure which gives sufficient cytological material for the correct diagnosis in 80% of cases. As with histological analysis of material from open biopsy, the cytological assessment must agree with the clinical and radiological findings

Aims

Accurate estimations of the risk of fracture due to metastatic bone disease in the femur is essential in order to avoid both under-treatment and over-treatment of patients with an impending pathological fracture. The purpose of the current retrospective in vivo study was to use CT-based finite element analyses (CTFEA) to identify a clear quantitative differentiating factor between patients who are at imminent risk of fracturing their femur and those who are not, and to identify the exact location of maximal weakness where the fracture is most likely to occur.

The most appropriate protocol for the biopsy of musculoskeletal tumours is controversial, with some authors advocating CT-guided core biopsy. At our hospital the initial biopsies of most musculoskeletal tumours has been by operative core biopsy with evaluation by frozen section which determines whether diagnostic tissue has been obtained and, if possible, gives the definitive diagnosis. In order to determine the accuracy and cost-effectiveness of this protocol we have undertaken a retrospective audit of biopsies of musculoskeletal tumours performed over a period of two years.

A total of 104 patients had biopsies according to this regime. All gave the diagnosis apart from one minor error which did not alter the management of the patient. There was no requirement for re-biopsy. This protocol was more labour-intensive and 38% more costly than CT-guided core biopsy (AU$1804 vs AU$1308). However, the accuracy and avoidance of the anxiety associated with repeat biopsy outweighed these disadvantages.