Osteoid osteoma of the foot : Presentation, treatment and outcome of a multicentre cohort.

BACKGROUND: Osteoid osteomas of the foot are rare, with a varying and atypical clinical as well as radiological presentation impeding early diagnosis and treatment. The aim of the present multicentre study was to 1) analyze epidemiological, clinical and radiological findings of patients with foot osteoid osteomas and to 2) deduce a diagnostic algorithm based on the findings. METHODS: A total of 37 patients (25 males, 67.6%, mean age 23.9 years, range 8-57 years) with osteoid osteomas of the foot were retrospectively included, treated between 2000 and 2014 at 6 participating tertiary tumor centres. Radiographic images were analyzed, as were patients' minor and major complaints, pain relief and recurrence. RESULTS: Most osteoid osteomas were located in the midfoot (n = 16) and hindfoot (n = 14). Painful lesions were present in all but one patient (97.3%). Symptom duration was similar for hindfoot and midfoot/forefoot (p = 0.331). Cortical lesions required fewer x­rays for diagnosis than lesions at other sites (p = 0.026). A typical nidus could be detected in only 23/37 of x­rays (62.2%), compared to 25/29 CT scans (86.2%) and 11/22 MRIs (50%). Aspirin test was positive in 18/20 patients (90%), 31 patients (83.8%) underwent open surgery. Pain relief was achieved in 34/36 patients (outcome unknown in one), whilst pain persisted in two patients with later confirmed recurrence. CONCLUSIONS: As previously reported, CT scans seem to be superior to MRIs towards detection of the typical nidus in foot osteoid osteomas. In patients with unclear pain of the foot and inconclusive x­rays, osteoid osteoma should be considered as differential diagnosis.

Tumor-associated mortality and prognostic factors in myxofibrosarcoma - A retrospective review of 109 patients.

BACKGROUND: Myxofibrosarcoma (MFS) is one of the most common sarcoma subtype in elderly patients. They are reported to recur locally independently of the tumour grade in 30-40% of cases and metastases are reported to develop in high-grade tumours in 20-35% cases. As MFS is a rare diagnosis, data investigating specific survival and independent risk factors are lacking and have mostly been limited to single orthopaedic oncology centre studies so far. Thus we set up a pathology-based retrospective study and analyzed all MFS diagnosed in our institution with the following aims: (1) analysis of independent risk factors for overall survival, disease specific survival, local recurrence-free survival and distant metastasis free survival following resection of MFS; (2) analysis of resection margin status. HYPOTHESIS: High-grade MFS have a low survival distant metastasis free survival and local recurrence free survival is dependent on surgical margin status. PATIENTS AND METHODS: We retrospectively analysed 109 patients (median 66 years [range, 21-96]) diagnosed with MFS and a median follow-up of 42 months at one centre between 1990 and 2014. Tumor-associated survival, including competing risk analysis, and prognostic factors for local recurrence, metastatic disease and death from disease were investigated and included in a multivariate analysis. RESULTS: Overall survival was 79% [95%CI: 71.9-87.5] at 3 years and 76% [95%CI: 67.4-84.6] at 5 years. Disease specific survival was 85% [95%CI: 78.4-92.2] at 3 years and 80% [95%CI: 72.2-88.2] at 5 years. There were local recurrences in 11/109 patients (10%). Local recurrence free survival (LRFS) was 95% [95%CI: 92.0-99.8] at 3 and 88% [95%CI: 84.3-96.4] at 5 years. Metastatic disease (n=25; 23%) occurred after a median follow-up of 10 months. Distant metastasis free survival was 78% [95%CI: 69.9-85.9] at 3 and 77% [95%CI: 68.4-84.8] at 5 years. R1 status at primary resection was an independent risk factor for decreased Local Recurrence-free survival (OR: 8.5, 95%CI: 1.59-49.79 [p=0.01]). Grading was an independent risk factor for decreased Disease specific survival (OR 13.4, 95%CI: 1.65-1734.84 [p=0.01]) and Distant metastasis free survival (OR 16.2, 95%CI: 2.0-2110.5 [p=0.004]). Primary resection achieved R0 margins in 63 (58%) of 109 patients. Margins were adequate significantly more often (p<0.001) in patients treated primarily at a sarcoma centre (R0=58/68, 85%) than in those treated primarily at non-sarcoma centres (R0= 5/41, 12%), whereby the latter significantly more often treated superficial tumours (p=0.001) with a size of less than 5cm (p<0.001). DISCUSSION: Patients with high-grade MFS had a poorer prognosis with respect to Disease specific survival/Distant metastasis free survival than low-grade MFS. Local recurrence did not significantly affect disease specific survival. LEVEL OF EVIDENCE: IV.

Expandable distal femur megaprosthesis: A European Musculoskeletal Oncology Society study on 299 cases.

BACKGROUND AND OBJECTIVES: Expandable distal femur prostheses have become more popular over the last decades, but scientific data is limited. METHODS: A retrospective study was performed, including cases treated between 1986 and 2019 in 15 European referral centers for bone sarcomas. RESULTS: A total of 299 cases were included. Average follow-up was 80 months (range, 8-287 months). Mean patient age was 10 years. Most (80%) of the implants were noninvasive growers and a fixed hinge knee was used more often (64%) than a rotating hinge. Most prosthetic designs showed good (>80%) implant survival at 10 years, but repeat surgery was required for 63% of the patients. The most frequent reason for revision procedure was the completion of lengthening potential. Noninvasive expandable implants showed less risk of infection compared to invasive growers (11.8% vs 22.9% at 10 years). No difference in aseptic loosening was found between cemented and uncemented stems. CONCLUSIONS: This study shows the increasing popularity of expandable distal femur prostheses, with overall good results for function and implant survival. However, repeat surgery is frequently required, especially in patients under the age of 10 years old. Infection is less frequent in noninvasive growers compared to implants that require invasive lengthening procedures.

Survival of osteosarcoma patients following diagnosis of synchronous skip metastases.

BACKGROUND: We aim to investigate the prognostic implications of synchronous skip metastases in osteosarcoma by presenting the largest single centre series to date. METHODS: Retrospective study of 21 osteosarcoma patients with skip metastases treated between 1983 and 2004. RESULTS: No statistical difference in overall survival was demonstrated when comparing presence of lung metastases to those without (p = 0.859). No statistical difference was found in overall survival according to age group (<18yrs vs >18yrs; p = 0.126), or to percentage chemotherapy-induced bone necrosis (<90% vs >90%; p = 0.056). CONCLUSIONS: The presence of skip metastases confers a very poor prognosis as an independent variable. LEVEL OF EVIDENCE: III.

How is the outcome of the Limb Preservation System™ for reconstruction of hip and knee?

BACKGROUND: Despite tremendous advantages in the development and application of megaprostheses in tumour and revision surgery, complications are still not infrequently observed. Only two studies investigating the outcome of the LPS™ system in the proximal femur and distal femur/proximal tibia have been published thus far. Herein, mid-term implant survival rates one of the largest cohort of patients treated with the LPS™-system are presented aiming tp answer: 1) How is the outcome of the LPS™ system in the proximal femur and distal femur/proximal tibia? 2) Which factors are associated with altered implant survival? 3) What is the cumulative risk of complications according to Henderson? HYPOTHESIS: The LPS™-system is associated with high complication rates that depend on implant site, with infections being most common. PATIENTS AND METHODS: Fifty-seven patients who received the LPS™-system at the proximal femur (n=31), distal femur (n=21) and proximal tibia (n=5) between 2004 and 2010 for oncological (n=40) or non-oncological (n=17) causes, were retrospectively included. Median follow-up was 5.0 years (range, 0-12.4 years). Complications were classified according to Henderson into instability/soft tissue failure (type 1), aseptic loosening (type 2), structural failure (type 3), periprosthetic infection (type 4), tumour progression (type 5). Competing-risk-analyses were applied to estimate implant survival with death as the competing event. RESULTS: Twenty-six patients (45.6%) developed a complication, of whom 9 (29.0%) had a proximal femoral and 17 (65.4%) a distal femoral/proximal tibial implant. Type 4 complications were most common (n=11), followed by type 3 (n=6, including 2 yoke-fractures), type 1 and 2 (n=4 each), and type 5 (n=1). The only factor associated with the development of complications in the multivariate model was a distal femoral/proximal tibial implant (hazard-ratio: 7.418, 95% confidence-interval: 2.193-26.096, p=0.001), irrespective of reason for reconstruction and use of muscular flaps. The cumulative-incidence of failure including all complications was 34.3%, 40.7% and 67.1% at 3, 5 and 10 years, respectively. DISCUSSION: The LPS™-system may be used for proximal femoral reconstructions both in the oncological and non-oncological setting. Rates of complications are higher in our cohort than reported in literature for other, comparable, megaprosthesis systems. Especially in the distal femur/proximal tibia, complication rates were high, partially attributable to the former implant design leading to fractures of the yoke-mechanism. As the implant has been remodelled after these issues became evident, there is no objection to use this megaprosthesis system today. LEVEL OF EVIDENCE: IV, Observational Study.

Comparison of three surgical treatment options for unicameral bone cysts in humerus.

Treatment of unicameral bone cysts (UBC) in the humerus with drainage screws is scarcely reported in the literature. The aim of this retrospective study was to compare drainage screws and alternative treatment methods with respect to the number of required surgical procedures to achieve sufficient UBC healing, postoperative fractures/recurrences/complications, and radiological outcome. Medical archives of two tertiary orthopedic referral centers were screened for all patients who were treated surgically for humeral UBC in the period 1991-2015 with a histologically/cytologically confirmed diagnosis. Sex, age, all surgical procedures, fractures, complications, recurrences, and the final radiological outcome were compared between patients treated with drainage screws, elastic intramedullary nails, or curettage with optional grafting. The study included 106 operated patients with a mean age of 10.3 years, with a mean follow-up of 5.7 years. The average number of UBC-related surgical procedures in sex-matched and age-matched treatment groups was 2.7 with drainage screws, 2.8 with intramedullary nails, and 3.5 with curettage/grafting (P=0.54). Intramedullary nails (odds ratio 0.20) and older age (odds ratio for each year 0.83) predicted a lower risk of postoperative UBC recurrence. Patients with drainage screws had the highest UBC recurrence rates and the lowest rates of changed initial treatment method. There was no difference between the treatment groups in the postoperative fracture rate, complications, or the final radiological outcome. UBC treatment in the humerus therefore requires approximately three surgical procedures, irrespective of the treatment modality chosen. Adding an elastic intramedullary nail to a humeral UBC cyst may reduce recurrence risk and prevent further fractures. Level of Evidence: Level III - therapeutic retrospective comparative study.

Observational retrospective study on socio-economic and quality of life outcomes in 41 patients with adolescent idiopathic scoliosis 5 years after bracing combined with physiotherapeutic scoliosis-specific exercises (PSSE).

PURPOSE: We analysed socio-economic- and health-related quality of life (primary outcome) and radiological outcome (secondary outcome) 5 years after full time rigid bracing (FTRB) plus physiotherapeutic scoliosis-specific exercises (PSSE) in adolescent idiopathic scoliosis. METHODS: We included 41 patients (38 female and 3 male) treated with FTRB (Chênau brace) and PSSE (Schroth) between 2001 and 2010. The study protocol included a clinical and radiological examination, the completion of the SRS-24 questionnaire and acquisition of data on socio-economic factors (educational and employment status) and physical activity. Descriptive statistics were used to analyse the data; differences between patients with mild (< 30°) and severe curves (30°-50°) regarding hrQoL outcomes were analysed using the Mann-Whitney U Test. RESULTS: Primary outcomes showed full employment (higher education, 39%, and full-time work, 61%) and the majority of the patients (79.9%) performing moderate sports two to four times per week. The SRS-24 questionnaire produced a total mean score (MS) of 4.0 (79.9%). Patients with mild curves had a significantly better total score (MS 4.1 vs. MS 3.8, p = 0.020) and were more satisfied with the treatment (MS 4.3 vs MS 3.9, p = 0.020). As to the secondary outcomes, from start of bracing to follow-up (a mean of 6.7 years after brace weaning), the average Cobb angle changed from 28.6° to 25.6° (range 4°-48°); in 51.2% the curve angles could be maintained after weaning. CONCLUSIONS: Compared with the literature, our results showed similar curve development and hrQoL (pain, self-image and function) and better results regarding satisfaction with treatment. In comparison with the average population, there were no disadvantages as to occupation, education and sports. These slides can be retrieved under Electronic Supplementary Material.

Detection of GNAS mutations in intramuscular / cellular myxomas as diagnostic tool in the classification of myxoid soft tissue tumors.

BACKGROUND: Intramuscular / cellular myxomas and low-grade myxofibrosarcomas are two different tumor entities with a significant histological overlap, especially if dealing with small biopsies. Despite the morphological similarities, they differ considerably in their biological behaviour. Intramuscular / cellular myxoma rarely shows signs of recurrence and never metastasizes, in contrast to myxofibrosarcoma that tends to recur more aggressively and to metastasize haematologically. Therefore, it is of great importance to distinguish these lesions - evaluation of GNAS mutation status could be of tremendous help. METHODS: We reviewed 13 cases with intramuscular / cellular myxomas. The 13 cases included 5 men and 8 women, aged from 33 to 71 years (mean age 55.5 years). Immunohistochemistry was performed as well as next generation sequencing. Ten cases were located in the lower extremities and three cases were located in the upper extremities. Two lesions were initially misdiagnosed as a low-grade myxofibrosarcoma. RESULTS: Performing next generation sequencing 12 out of 13 specimens showed a GNAS mutation. CONCLUSIONS: Our findings demonstrate that GNAS mutations are more common in intramuscular / cellular myxomas, than had been reported in literature in the past. Next generation sequencing for determining GNAS mutation status on small biopsies or diagnostically challenging cases facilitates the diagnosis of intramuscular / cellular myxoma and separates this tumor entity from its mimics.

When Do Orthopaedic Oncologists Consider the Implantation of Expandable Prostheses in Bone Sarcoma Patients?

INTRODUCTION: Indications discussed for the implantation of expandable prostheses in bone sarcoma patients are unclear. This survey aimed to analyse common practice with this implant type in orthopaedic oncology. METHODS: A web-based survey was sent to 98 orthopaedic oncology surgeons. Factors reported in literature to influence the decision on the implantation of a growing prosthesis were covered in individual questions and three case scenarios. RESULTS: The completion rate of the survey was 45% (n = 44). Twenty-seven of 44 surgeons (61%) had implanted between 1 and 15 expandable prostheses within three years. The minimum median patient age was 6.5 years, and 3-5 cm of predicted growth deficit was the minimum before implanting a growing prosthesis. One-third of surgeons do not use growth calculation methods. Two out of three surgeons would rather not implant a growing prosthesis in children with metastatic disease. CONCLUSIONS: Our survey confirmed the literature with 3-4 cm as the minimum estimated growth deficit. The minimum age for the implantation of a growing prosthesis is approx. 6.6 years, and therefore the patients are younger than those reported in previous publications. One-quarter of orthopaedic surgeons do not use growing prostheses at all. It remains unclear whether growing prostheses are indicated in patients with metastatic disease.

Secondary tumours of the ampulla of Vater: Case report and review of the literature.

Secondary tumours of the ampulla of Vater are rare. Underlying primary tumours, clinical presentation, macroscopic appearance, treatment strategies and outcome of secondary ampullary lesions have not been systematically analysed. The present case study reported a 57-year old patient with an ampullary metastasis from renal cancer and a literature review was performed in which a further 32 patients were included. The most common responsible primary tumours were malignant melanoma and renal clear cell carcinoma, followed by breast cancer. The time interval between the diagnosis of the primary tumour and the ampullary metastasis was highly variable, and may be as long as 10 years, particularly for renal cancer. Patients may present with unspecific abdominal discomfort, jaundice or upper gastrointestinal bleeding. The gross appearance was largely indistinguishable from that of a primary tumour. Lesions may present as polypoid or irregular, soft and friable tumour mass, in certain cases with superficial ulceration. In ~50% of cases, the ampullary metastasis was the only metastatic lesion, while in the remaining cases, the cancer had spread to one or more organs. The prognosis was generally poor. The management requires a multi-modal approach, including endoscopic, surgical and oncological procedure.

Secondary tumors of the GI tract: origin, histology, and endoscopic findings.

BACKGROUND AND AIMS: The GI tract is rarely affected by secondary tumors. Patients often present at an advanced stage of the disease, and prognosis is dismal. This study aimed to analyze the clinical, endoscopic, and pathologic features of secondary tumors that had been diagnosed endoscopically. METHODS: We conducted a retrospective database analysis of 217 patients with secondary tumors of the GI tract. Endoscopic findings and histologic diagnoses were systematically re-evaluated. RESULTS: Malignant melanoma (n = 33, 15%), breast cancer (n = 32, 15%), and pancreatic cancer (n = 27, 12%) were the most common corresponding primaries. About one-third of secondary tumors were detected in the stomach (n = 76, 35%), followed by small intestine (n = 54, 25%) and rectum (n = 53, 24%). The median time between the diagnoses of primary and secondary tumors was 19 months (mean, 31; range, 0-251), and this time was particularly long for renal cell carcinoma and breast cancer (median, 38 and 45 months, respectively). Direct invasion from extra-GI malignancies was more common (56%) than vascular cancer spread (44%) and depended on both sites of tumor involvement and corresponding primary. The lesions presented with various endoscopic patterns. In patients for whom a definitive diagnosis of cancer was known before the examination (n = 168), a secondary tumor was included in the differential diagnosis in only 48% of lesions. It is of note that the remaining cases were diagnosed endoscopically as primary tumors and rarely also as nonneoplastic change. CONCLUSIONS: Secondary tumors may affect all parts of the GI tract. Malignant melanoma and breast and pancreatic cancer represent the most common primaries. Diagnosis based on examination of biopsy specimens is crucial to avoid misclassification.

Expanded molecular profiling of myxofibrosarcoma reveals potentially actionable targets.

Myxofibrosarcomas are morphologically heterogeneous soft tissue sarcomas lacking a specific immunohistochemical expression profile and recurrent genetic changes. The study was designed to gain further insights into the molecular landscape of myxofibrosarcomas by targeted re-sequencing of known cancer driver hotspot mutations and the analysis of genomewide somatic copy number alterations. A well-defined group of myxofibrosarcomas, including myxofibrosarcomas G1 (n=6), myxofibrosarcomas G3 (n=7), myxofibrosarcomas with morphologically heterogeneous and independently selectable G1 and G3 areas within a tumor (n=8), and myxofibrosarcomas G3 with subsequent tumor recurrence (n=1) or metastatic disease (n=3) were evaluated. Mutational analysis demonstrated mutations in TP53, PTEN, FGFR3, CDKN2A, and RB1. TP53 mutations were seen in 11 (44%) of patients and detected in myxofibrosarcomas G1, G3, with heterogeneous morphology and G3 with subsequent metastases in 1 patient (16%), 3 patients (42%), 2 patients (62.5%), and 3 patients (75%), respectively. Additional mutations were detected in 2 patients, intratumoral mutational heterogeneity in 1 patient. We observed a variety of copy number alterations typical for myxofibrosarcomas, with higher numbers in G3 compared with G1 myxofibrosarcomas. Cluster analysis revealed distinctive features especially in metastatic and recurrent disease. Focal alterations affected CDKN2A, CCND1, CCNE1, EGFR, EPHA3, EPHB1, FGFR1, JUN, NF1, RB1, RET, TP53, and additional novel amplifications in CCNE1, KIT, EGFR, RET, BRAF, NTRK2 were seen in G3 compared with the G1 tumor areas. The total number of focal events in G1 versus G3 tumors differed significantly (P=0.0014). TRIO and RICTOR co-amplification was seen in 8 (44%) G3 and 1 (10%) G1 myxofibrosarcomas and RICTOR amplification alone in 4 (40%) G1 myxofibrosarcomas. TRIO amplification was significantly (P=0.0218) higher in G3 myxofibrosarcomas indicating a late genetic event. These findings support the use of expanded molecular profiling in myxofibrosarcomas to detect drug-able targets to allow patients to participate in basket trials.

Case Report: Epstein-Barr-Virus negative diffuse large B-cell lymphoma detected in a peri-prosthetic membrane.

BACKGROUND: Primary bone lymphomas (PBL) are extremely rare malignant neoplasms. The most commonly described subtype of PBL is diffuse large B-cell lymphoma (DLBCL). DLBCL within peri-prosthetic membrane of a joint is exceedingly rare. To the best of our knowledge this case is the second reported Epstein-Bar-Virus (EBV) negative DLBCL in a peri-prosthetic membrane in the literature. CASE PRESENTATION: We report an 80 year old female patient who developed a DLBCL with chronic inflammation in association to a metallic implant in the left knee. This lymphoma in contrast to the usually described DLBCL in the peri-prosthetic membrane was EBV negative by EBER in situ hybridization as well as by polymerase chain reaction (PCR). CONCLUSION: This report challenges the concept of DLBCL associated with chronic inflammation and raises the question of other pathogenetic factors involved in the pathogenesis of this rare disease.

The incidence of implant fractures after knee arthroplasty.

PURPOSE: This study aimed to evaluate the incidence of "implant" fractures after knee arthroplasty using clinical literature and worldwide arthroplasty registers. The hypothesis was that register datasets report higher rates of these rare complications than clinical studies. METHODS: Calculations were based on the pooled incidence of revision operations after fractures of knee arthroplasties, comparing clinical studies published in MEDLINE-listed journals and annual reports from worldwide arthroplasty registers in a structured literature analysis based on a standardized methodology. RESULTS: Twelve clinical studies and datasets from six worldwide registers were included. Rates of fractures of knee arthroplasties were reported from 0.2 to 2.5 % in clinical studies versus 0.02-0.17 % in worldwide arthroplasty registers. CONCLUSIONS: Fractures of knee arthroplasty systems are rare complications, with clinical studies showing higher incidence rates than worldwide arthroplasty registries. Unicompartmental knee arthroplasty (UKA) implanted before 2000, constrained primary or revision constrained total knee arthroplasties, and patellar replacements showed the highest incidence of implant fracture. The results of this analysis can help clinicians to counsel patients on potential complications following knee arthroplasty. LEVEL OF EVIDENCE: III.

Is superior tibiofibular joint resection necessary in extraarticular knee resection for sarcomas? A systematic review.

BACKGROUND: Sarcomas infiltrating the knee joint require extraarticular resection to achieve wide margins. Opinions differ as to whether the superior tibiofibular joint (STFJ) is part of the knee joint and should be removed in the course of extraarticular resection. Thus, we investigated the frequency of communication between the tibiofemoral joint (TFJ) and the STFJ, and the reported local recurrence rates (LRR) following extraarticular knee resection. METHODS: A systematic literature review on STFJ and TFJ communication and local recurrence rates following extraarticular knee resections was undertaken. RESULTS: Cadaver studies detected communication between the TFJ and STFJ in 10-64% of the cases. Direct arthrography with physical loading verified a 100% communication rate. Regarding the extent of extraarticular knee resection, two institutions where the STFJ was resected had a LRR of 4-8%, while studies from another three where the STFJ was not routinely resected reported a LRR of 0-21%. CONCLUSIONS: Since the literature reports about a 100% communication rate between the TFJ and the STFJ, resection of the STFJ in patients with sarcomas involving the knee joint would seem to be indicated, although it is not clear whether resection of the STFJ reduces local recurrence rates.

Metastatic Potential of Grade I Chondrosarcoma of Bone: Results of a Multi-institutional Study.

BACKGROUND: Little is known about the metastatic potential of low-grade chondrosarcoma. This study was designed to evaluate the rate of metastasis to identify possible risk factors. METHODS: The files of 225 patients with newly diagnosed, grade I chondrosarcoma of bone treated between 1975 and 2012 were retrospectively analyzed. Median follow-up was 80 months for survivors (range 24-445 months). Nonparametric analyses were performed with the Mann-Whitney U test. Survival curves were calculated with the Kaplan-Meier method and compared with the log-rank test. RESULTS: Fourteen patients developed metastases after a median of 49 months. Metastasis-free survival probability (MFS) was 95 % at 5 years and 92 % at 10 years. Post-metastasis survival probability amounted to 27 % after 5 years. Tumor size at diagnosis (P = 0.698) and surgical margin width (P = 0.514) had no influence on MFS. Patients who developed local recurrences had a significantly lower 10-year MFS than patients without recurrences (69 % vs. 99 %, P < 0.001). Patients with grade I recurrences had a significantly poorer MFS than patients without recurrences (P = 0.013) but a significantly higher MFS than patients with grade II recurrences (P = 0.006). Patients with thoracic wall tumors had a significantly lower 10-year MFS of 66 % compared with patients with tumors of the upper (100 %, P < 0.001) and lower extremity (93 %, P = 0.033). CONCLUSIONS: The biological behavior of low-grade chondrosarcoma appears to be more consistent with the WHO definition of rarely metastasizing bone tumors, rather than the one of locally aggressive neoplasms. Thoracic wall tumors and the development of local recurrences were associated with a higher metastasis rate in this study.

Is wide resection obsolete for desmoid tumors in children and adolescents? Evaluation of histological margins, immunohistochemical markers, and review of literature.

Desmoid fibromatosis is a benign fibroblastic neoplasm with high recurrence rates predominantly observed in pediatric and adolescent patients. The use of wide resection margins has been discussed controversially in literature. In addition, data on non-surgical treatment is limited as phase III studies are still missing. Nineteen patients under the age of 18 years were identified. Tumor location, surgical treatment for primary or recurrent tumors, resection margins, medical neo-/adjuvant treatment, time to recurrence as well as immunohistochemical markers (estrogen receptor, ER α and ß, progesterone and androgen receptors, somatostatin, Ki-67, c-kit, platelet-derived growth factor receptors, PDGFRs, α and ß, ß-catenin) were evaluated. The mean age at diagnosis was 6.6 years, with a mean follow-up of 114 months. Recurrences were detected in four out of nineteen patients. Surprisingly, the recurrence rate was not influenced by type of resection used (R0, R1/2). All samples were tested negative for ER α, somatostatin, and progesterone receptor. In contrast, a majority of tumors showed positive results for PDGFR α and ß and ß-catenin. No correlation between positive immunohistochemical markers and tumor recurrences was detectable. In conclusion, recurrence rates are not depending on resection type and immunohistochemical markers seem to behave differently in children and adolescents in contrast to adult patients.

Paley's multiplier method does not accurately predict adult height in children with bone sarcoma.

BACKGROUND: The majority of patients with osteosarcoma and Ewing's sarcoma are diagnosed before skeletal maturity. Paley's multiplier is used for height prediction in healthy children, and has been suggested as a method to make growth predictions for children with osteosarcoma and Ewing's sarcoma when considering limb salvage options. To our knowledge, no evaluation of this method in this particular patient group has been performed, but a temporary growth deficit has been observed in children undergoing chemotherapy. QUESTIONS/PURPOSES: We asked whether (1) Paley's formula reliably predicts growth in children who received polychemotherapy; (2) chemotherapy impairs growth velocity; and (3) final adult height is impaired in these patients. METHODS: Retrospectively, data for 94 patients with osteosarcoma and Ewing's sarcoma were retrieved from databases of two sarcoma centers. Onset before 14 years of age in girls and 16 years in boys and a minimum followup until 18 years were required (mean, 67 months; range, 31-124 months) criteria. Exclusion criteria were the intake of growth hormones or no chemotherapy. Thirty-three patients (35%) fulfilled all inclusion criteria. Predicted adult heights were compared with actual adult height. The development of a growth deficit was evaluated for 23 children (without chemotherapy for recurrence) using age- and gender-specific standard deviation scores for height (WHO Z-scores). RESULTS: Height prediction using Paley's method showed a high percentage of false predictions (outside ± 1 SD, 70%; outside ± 2 SD, 61%). On average, the mean total height of the patients was overestimated (2.3 cm). The median absolute error of prediction was 5.0 cm (range, -17 to 8). Patients with osteosarcoma and Ewing's sarcoma showed a significant growth impairment during polychemotherapy. A catchup phase in growth before skeletal maturity was observed in patients with osteosarcoma but not with Ewing's sarcoma. CONCLUSIONS: Owing to its lack of reliability in this patient group, methods other than Paley's should be evaluated to predict adult height. Although limited by a small number of patients, our study results indicate a decreased adult height in patients with bone sarcoma after chemotherapy. LEVEL OF EVIDENCE: Level III, therapeutic study. See the Instructions for Authors for complete description of levels of evidence.

Central low-grade osteosarcoma with an unusual localization in the diaphysis of a 12-year old patient.

BACKGROUND: Low-grade central osteosarcoma is a very rare subtype of osteosarcoma with a predilection for the metaphysis of long bones and a peak incidence in the 3(rd) decade of life. Absence of specific clinical symptoms and a good prognosis after wide resection are the characteristics of this entity. Chemotherapy is not indicated in this highly differentiated tumour. CASE REPORT: A 12-year old girl presented with limping, swelling and pain in the mid of the left femur. Radiography showed a 12 cm long intraosseous expansion with lamellated periosteal reaction and contrast medium enhancement in MRI. Although radiology led to the differential diagnoses of Ewing's sarcoma, osteomyelitis and fibrous dysplasia, the histological specimen showed a hyopocellular spindle-cell proliferation arranged in fascicles with mild cytologic atypia and only single mitotic figures. In synopsis with radiology the diagnosis of low-grade central osteosarcoma was made and confirmed by reference pathology. The tumour was resected with wide margins and reconstruction was performed with a vascularized fibula, a homologous allograft and a plate. Staging was negative for recurrence and metastasis at a follow-up of 16 months. CONCLUSIONS: Low-grade osteosarcoma accounts for only 1% of all osteosarcomas with a peak incidence in the 3(rd) decade. The diaphyseal localization and the young age make this case special. To achieve the correct diagnosis of this rare low-grade entity and thereby the adequate treatment, despite a wide range of differential diagnoses, a multidisciplinary approach is essential.