Purpose:Simple bone cysts are among the most prevalent benign cystic tumor-like lesions in children. Proximal femoral simple bone cysts may require specific treatment because of increased fracture... Show morePurpose:Simple bone cysts are among the most prevalent benign cystic tumor-like lesions in children. Proximal femoral simple bone cysts may require specific treatment because of increased fracture risk. With limited literature available on this specific localization, consensus regarding optimal treatment is lacking. We present a large international multicenter retrospective cohort study on proximal femoral simple bone cysts.Methods:All consecutive pediatric patients with proximal femoral simple bone cyst from 10 tertiary referral centers for musculoskeletal oncology were included (2000–2021). Demographics, primary treatment, complications, and re-operations were evaluated. Primary outcomes were time until full weight-bearing and failure-free survival.Results:Overall, 74 simple bone cyst patients were included (median age 9 years (range = 2–16), 56 (76%) male). Median follow-up was 2.9 years (range = 0.5–21). Index procedure was watchful waiting (n = 6), percutaneous procedure (n = 12), open procedure (n = 50), or osteosynthesis alone (n = 6). Median time until full weight-bearing was 8 weeks (95% confidence interval = 0.1–15.9) for watchful waiting, 9.5 (95% confidence interval = 3.7–15.3) for percutaneous procedure, 11 (95% confidence interval = −0.7 to 13.7) for open procedure, and 6.5 (95% confidence interval = 5.9–16.1) for osteosynthesis alone (p = 0.58). Failure rates were 33%, 58%, 29%, and 0%, respectively (p = 0.069). Overall failure-free survival at 1, 2, and 5 years was 77.8% (95% confidence interval = 68.2–87.4), 69.5% (95% confidence interval = 58.5–80.5), and 62.0% (95% confidence interval = 47.9–76.1), respectively.Conclusion:A preferred treatment for proximal femoral simple bone cysts remains unclear, with comparable failure rates and times until full weight-bearing. Watchful waiting may be successful in certain cases. If not feasible, osteosynthesis alone can be considered. Treatment goals should be cyst control, minimizing complications and swift return to normal activities. Therefore, an individualized balance should be made between undertreatment, with potentially higher complication risks versus overtreatment, resulting in possible larger interventions and accompanying complications.Level of evidence:Level IV, retrospective multicentre study Show less
BackgroundExtra-abdominal desmoid tumor fibromatosis (DTF) is a rare, locally aggressive soft tissue tumour. The best treatment modality for this patient cohort is still object of debate.Questions... Show moreBackgroundExtra-abdominal desmoid tumor fibromatosis (DTF) is a rare, locally aggressive soft tissue tumour. The best treatment modality for this patient cohort is still object of debate.Questions/purposeThis paper aimed to (1) to compare the outcomes of DTF after different treatment modalities, (2) to assess prognostic factors for recurrence following surgical excision, and (3) to assess prognostic factors for progression during observation.MethodsThis was a retrospective multicenter study under the patronage of the European Musculoskeletal Oncology Society (EMSOS). All seven centres involved were tertiary referral centres for soft tissue tumours. Baseline demographic data was collected for all patients as well as data on the diagnosis, tumour characteristics, clinical features, treatment modalities and whether they had any predisposing factors for DTF.ResultsThree hundred eighty-eight patients (240 female, 140 male) with a mean age of 37.6 (18.8 SD, range: 3-85) were included in the study. Two hundred fifty-seven patients (66%) underwent surgical excision of ADF, 70 patients (18%) were observed without therapy, the residual patients had different conservative treatments. There were no significant differences in terms of tumour recurrence or progression between the different treatment groups. After surgical excision, younger age, recurrent disease and larger tumour size were risk factors for recurrence, while tumours around the shoulder girdle and painful lesions were at risk of progression in the observational group.ConclusionLocal recurrence rate after surgery was similar to progression rates under observation. Hence, observation in DTF seems to be justified, considering surgery in case of dimensional progression in 2 consecutive controls (3 and 6months) and in painful lesions, with particular attention to lesions around the shoulder girdle. Show less
