Dual pedicle epiphyseal transfer for paediatric bony sarcoma reconstruction: Technique and review of outcomes.

Skeletal reconstruction after tumour resection in paediatric patients is challenging. The resultant reconstruction needs to meet the demands of graft incorporation as well as the potential for growth. The vascularised fibular epiphyseal transfer (VFET) offers the potential for both. We retrospectively reviewed eight paediatric patients treated with VFET after bony tumour resection. All patients underwent a dual pedicle transfer with the peroneal artery for the diaphyseal blood supply and the recurrent branch of the anterior tibial artery for the physis. This is the largest series in literature for dual pedicle transfers for bony reconstruction. We present our surgical technique and outcomes in terms of functional limb salvage and growth.

Malignant giant cell tumour of bone: a review of clinical, pathological and imaging features.

Giant cell tu mour accounts for up to 5% of all bone tumours and malignant giant cell tumour arises in < 10% of cases, representing sarcomatous transformation. Primary malignant giant cell tumour of bone occurs when sarcomatous tissue is observed within conventional giant cell tumour histologically on initial presentation. Secondary malignant giant cell tumour of bone occurs in a region of previously treated giant cell tumour, with most cases arising due to prior radiotherapy. Malignancy in giant cell tumour of bone does not have any unique clinical or imaging features compared to conventional aggressive disease. Historically, malignant giant cell tumour of bone has a poor prognosis which is worse in cases of secondary malignancy. This article aims to present the clinical, pathological and imaging features of MGCTB based on a review of the literature and illustrated by examples from our experience.

Reconstruction with a Custom made Prosthetic Wrist Arthrodesis after Bone Tumor Resections of the Distal Radius. Single Centre Experience.

Objective The present study aimed at analyzing the clinical, radiological and functional results of the reconstruction of the distal radius after tumor resection with a custom-made metal arthrodesis implant and compare them with other types of distal radius reconstruction, as presented in the literature. To our best knowledge, this is the first article describing this particular type of implant and patient functionality. Methods Functional outcomes of reconstruction of the distal radius were assessed in a series of 4 patients. Three of the patients having had resection of giant cell tumors (GCTs), one patient having had resection of osteosarcoma. Results There were no major implant-related complications like infection, nonunion or loosening. Two patients had to undergo further surgery for protruding metalwork. Overall function was good according to the Musculoskeletal Tumor Society MSTS and Disabilities of the Arm, Shoulder, and Hand (DASH) scores. Conclusion The present study shows that custom-made metal arthrodesis implant benefits from the fact that it can be used as a salvage option when other treatments have failed, or it can be used as a primary option in cases in which there is limited bone stock after distal radius tumor resection.

An update on the imaging of diaphyseal aclasis.

Solitary osteochondromas are common, benign hyaline cartilage-capped exostoses that primarily arise from the metaphyses of long and flat bones. Diaphyseal aclasis is an autosomal dominant condition resulting from EXT1 or EXT2 gene mutations and is characterized by multifocal osteochondromas. These can result in a wide spectrum of complications, such as skeletal deformity, neurological and vascular complications, adventitial bursa formation, fracture, and rarely malignant transformation to peripheral chondrosarcoma. In this review, we outline in detail the multimodality imaging features of DA and its associated complications.

Reconstruction with a Custom made Prosthetic Wrist Arthrodesis after Bone Tumor Resections of the Distal Radius. Single Centre Experience / Reconstrução com implante metálico personalizado de artrodese após ressecções de tumor ósseo do rádio distal. Experiência em um único centro

Abstract Objective The present study aimed at analyzing the clinical, radiological and functional results of the reconstruction of the distal radius after tumor resection with a custom-made metal arthrodesis implant and compare them with other types of distal radius reconstruction, as presented in the literature. To our best knowledge, this is the first article describing this particular type of implant and patient functionality. Methods Functional outcomes of reconstruction of the distal radius were assessed in a series of 4 patients. Three of the patients having had resection of giant cell tumors (GCTs), one patient having had resection of osteosarcoma. Results There were no major implant-related complications like infection, nonunion or loosening. Two patients had to undergo further surgery for protruding metalwork. Overall function was good according to the Musculoskeletal Tumor Society MSTS and Disabilities of the Arm, Shoulder, and Hand (DASH) scores. Conclusion The present study shows that custom-made metal arthrodesis implant benefits from the fact that it can be used as a salvage option when other treatments have failed, or it can be used as a primary option in cases in which there is limited bone stock after distal radius tumor resection.

Resumo Objetivo O presente estudo teve como objetivo analisar os resultados clínicos, radiológicos e funcionais da reconstrução do rádio distal após a ressecção do tumor com implante metálico personalizado de artrodese e compará-los com outros tipos de reconstrução do rádio distal, conforme apresentado na literatura. Pelo que conhecemos, este é o primeiro artigo descrevendo esse tipo particular de implante e funcionalidade no paciente. Métodos Os desfechos funcionais de reconstrução do rádio distal foram avaliados em uma série de 4 pacientes. Três dos pacientes tiveram ressecção de tumores de células gigantes (TCGs), sendo um paciente com ressecção de osteossarcoma. Resultados Não houve complicações relacionadas ao implante, como infecção, não sindicalidade ou afrouxamento. Dois pacientes tiveram que passar por uma nova cirurgia para a protusão da prótese metálica. A função geral foi boa de acordo com as pontuações da Musculoskeletal Tumor Society (MSTS) e Disabilities of the Arm, Shoulder, and Hand (DASH). Conclusão O estudo mostra que o implante metálico personalizado de artrodese se beneficia do fato de que pode ser usado como opção de salvamento quando outros tratamentos falharam, ou pode ser usado como opção primária nos casos em que há estoque ósseo limitado após a ressecção do tumor do rádio distal.

Managing NON-DIAGNOSTIC biopsies in musculoskeletal tumours in a specialist centre: Deciding on the algorithm.

INTRODUCTION: Core needle biopsy is an effective method of obtaining tissue diagnosis. However, a diagnostic dilemma arises when lesional tissue is non-diagnostic which obviates considering radiological guided re-biopsy (RB) or an open surgical biopsy but the question raised is which serves as a better diagnostic tool. PATIENT AND METHODS: We retrospectively reviewed data from a prospectively collected database of 4516 core needle biopsies performed in our specialist musculoskeletal tumour centre over a 6-year period. Our aim was to evaluate the management of non-diagnostic biopsies (NDB) and establish a safe and accurate diagnostic strategy in the presence of a NDB. RESULTS: Two hundred fifteen (4.8%) NDB cases with complete follow-up were identified. Of these 157 (73%) were treated definitively on the basis of imaging and 58 (27%) had a RB, 48 (83%) of which led to a positive histological diagnosis. The remaining 10 were again non-diagnostic giving a total of 167 patients being treated definitively without a tissue diagnosis. The sensitivity and specificity for multidisciplinary team (MDT) assessment as a diagnostic tool was 0.75 and 0.88 respectively while that for RB was 0.91 and 0.9. CONCLUSION: Re-biopsy after first non-diagnostic core needle biopsy offers high sensitivity and specificity, especially in the presence of malignancy. In the absence of tissue diagnosis, however, MDT assessment is also highly accurate and a safe strategy in managing this complex group of patients. LEVEL OF EVIDENCE: Diagnostic Level III.

Functional outcome following primary total knee arthroplasty cannot be predicted using the initial post-operative radiograph.

Obtaining standardised post-operative radiographs following total knee arthroplasty is common practice. Little is known regarding how measurements taken from the initial post-operative radiograph correlate to functional outcome. The initial post-operative radiographs for 110 primary total knee arthroplasties were reviewed retrospectively. Femoral and tibial component alignment was measured by two independent consultant radiologists. Functional outcome was assessed by the Oxford Knee Score pre-operatively and one year post-operatively. Correlation was determined by Pearson correlation analysis. There was no significant correlation between the radiographic measurements with the one year post-operative Oxford Knee Score nor was there significant correlation with the difference in pre-operative and post-operative scores. The initial post-operative radiograph cannot be used as a tool to reliably predict functional outcome at one year.

Prognostic Factors in the Operative Management of Sacral Chordomas.

OBJECTIVE: Surgical resection of sacral chordomas offers the best long-term prognosis but has high rates of local recurrence, metastases, and mortality. Most prognostic studies are limited by low patient numbers, variation in treatment, follow-up, and prognostic variables studied. The objective of this study was to identify factors associated with recurrence, metastasis, and survival. METHODS: Retrospective review of 58 patients undergoing sacrectomy for chordoma with a mean age of 63 years (range: 41-80 years) and a mean follow-up of 45.3 months (range: 2-144 months). Data on prognostic variables and outcomes were collected. Forty-two patients underwent a combined anterior and posterior approach and 16 underwent a posterior-only approach. RESULTS: Twenty-six patients (44.8%) died during follow-up. Kaplan-Meier estimates for 5- and 10-year survival were 62% and 26%, respectively. Local recurrence occurred in 32 patients (51.7%) and metastases in 19 (32.7%). Adequacy of resection margins was the most important predictor of disease recurrence, metastases, and survival. Tumors >8 cm were associated with significantly increased risk of metastases and reduced survival (P < 0.05). Dedifferentiated disease and infiltration of the sacroiliac joints and/or adjacent musculature were also associated with reduced survival. Median survival was 23 months for patients with gluteus maximus invasion, 66 months for gluteus maximus and piriformis invasion, 67 months for piriformis invasion, and 90 months for patients with no muscle invasion. CONCLUSIONS: Patients with inadequate resection margins, tumors >8 cm, sacroiliac joint and/or musculature infiltration, and dedifferentiated disease have significantly worse oncologic outcomes. Involvement of gluteus maximus alone confers a higher risk of metastases and local recurrence than involvement of piriformis and gluteus maximus, or piriformis alone.

Hydroxyapatite-coated collars reduce radiolucent line progression in cemented distal femoral bone tumor implants.

BACKGROUND: Aseptic loosening of massive bone tumor implants is a major cause of prosthesis failure. Evidence suggests that an osteointegrated hydroxyapatite (HA)-coated collar would reduce the incidence of aseptic loosening around the cemented intramedullary stem in distal femoral bone tumor prostheses. Because these implants often are used in young patients with a tumor, such treatment might extend the longevity of tumor implants. Questions/purposes We asked whether (1) HA-coated collars were more likely to osteointegrate; (2) HA collars were associated with fewer progressive radiolucent lines around the stem-cement interface; and (3) HA-coated collars were associated with less bone loss at the bone-shoulder implant junction? METHODS: Twenty-two patients were pair-matched to one of two groups--either (1) implants with a HA-coated ingrowth collar (HA Collar Group); or (2) implants without an ingrowth collar (Noncollar Group). Age, sex, and length of followup were similar in both groups. HA-coated collars were developed and used at our institution from 1992 to address the high failure rate attributable to aseptic loosening in patients with massive bone tumor implants. Before this, smooth titanium shafts were used routinely adjacent to bone at the transection site. The minimum followup was 2 years (mean, 7 years; range, 2-12 years). Radiographs obtained throughout the followup period were analyzed and osteointegration at the shaft of the implant quantified. Radiolucent line progression around the cemented stem was semi-quantitatively assessed and cortical bone loss at the bone-shoulder implant junction was measured during the followup period. RESULTS: Comparison of the most recent radiographs showed nine of 11 patients had osteointegrated HA collars, whereas only one patient in the Noncollar Group had osteointegration (p > 0.001). The radiolucent line score quantified around the cemented stem was lower in the HA Collar Group when compared with the Noncollar Group (p = 0.001). Results showed an increase in cortical bone loss at the bone-shoulder implant junction in the Noncollar Group when compared with the HA Collar Group (p < 0.001). CONCLUSIONS: Osteointegration at the implant collar resulted in fewer radiolucent lines adjacent to the intramedullary cemented stem and decreased cortical bone loss immediately adjacent to the transection site. These results suggest that the HA collar may help reduce the risk of aseptic loosening in patients with this type of implant, but longer followup and a larger prospective comparison series are necessary to prove this more definitively.

Clinical outcome in patients with peripherally-sited atypical lipomatous tumours and dedifferentiated liposarcoma.

The reported incidence of local recurrence of peripheral atypical lipomatous tumours is highly variable and is likely to reflect the different inclusion criteria of cases, and the design of previous studies. We aimed to study the incidence of local recurrence of 90 cases of atypical lipomatous tumours and an additional 18 cases of de novo dedifferentiated liposarcoma. All tumours were diagnosed on the basis of MDM2 amplification: all patients had their first treatment in the same specialist sarcoma unit and were followed for a minimum of 60 months. The tumours were diagnosed between 1997 and 2009 and followed until the end of 2014. Seventy cases (78%) of atypical lipomatous tumours were located in the thigh (mean size 195 mm on presentation). Eight atypical lipomatous tumours (8.9%) recurred locally, of which 50% recurred after 60 months. The only two tumours with intralesional excisions recurred. Seven of the eight recurrent tumours were detected by the patient by self-examination. One case recurred a second time as a dedifferentiated liposarcoma. Seventeen per cent of the de novo dedifferentiated liposarcomas recurred within 60 months of presentation. Extending the study period revealed that atypical lipomatous tumour could recur up to 40 years after the first surgery. Furthermore, of 26 tumours that recurred in the extended study, 27% recurred more than once, and three of the seven that recurred more than once transformed into a dedifferentiated liposarcoma. We recommend that, following post-operative wound care, patients with atypical lipomatous tumour are referred back to their general practitioner for follow up, but that in the event of a suspected recurrence they have rapid access back to the specialist unit using a 'supported discharge' scheme. In the event of an intralesional excision and if a lesion recurs, patients are followed in a specialist unit at regular intervals: whether MRI scanning is a valuable means of monitoring such patients is unclear and requires an evidence base.

Custom rotating hinge total knee arthroplasty in patients with poliomyelitis affected limbs.

PURPOSE: Total knee arthroplasty (TKA) in limbs affected by poliomyelitis is a technically challenging procedure. These patients often demonstrate acquired articular and metaphyseal angular deformities, bone loss, narrowness of the intramedullary canals, impaired quadriceps strength, flexion contractures and ligamentous laxity producing painful hyperextension. Thus, using condylar knee designs in these patients will likely result in early failure because of instability and abnormal load distribution. The aim of this study was to assess the outcomes associated with use of the customised (SMILES) rotating-hinge knee system at our institution for TKA in poliomyelitis-affected limbs. METHODS: We retrospectively reviewed the outcome of 14 TKAs using the (SMILES) prosthesis in 13 patients with limbs affected by poliomyelitis. All patients had painful unstable knees with hyperextension. There were ten females and three males with a mean age of 66 years (range 51-84) at time of surgery. Patients were followed up clinically, radiologically and functionally with the Oxford knee score (OKS). Mean follow-up was 72 months (16-156). RESULTS: There were no immediate or early complications. One patient fell and sustained a peri-prosthetic fracture at seven months requiring revision to a longer stem. Radiological evaluation showed satisfactory alignment with no signs of loosening in all cases. Mean OKS improved from 11.6 (4-18) to 31.5 (18-40) postoperatively (p < 0.001). CONCLUSION: The rotating hinge (SMILES) prosthesis is effective at relieving pain and improving function in patients with poliomyelitis. The device compensates well for ligamentous insufficiency as well as for any associated bony deformity.

Isocitrate dehydrogenase 1 mutations (IDH1) and p16/CDKN2A copy number change in conventional chondrosarcomas.

To determine whether IDH1 mutations are present in primary and relapsed (local and distal) conventional central chondrosarcomas; and secondly, to assess if loss of p16/CDKN2A is associated with tumour grade progression, 102 tumour samples from 37 patients, including material from presenting and relapse events, were assessed. All wild-type cases for IDH1 R132 substitutions were also tested for IDH2 R172 and R140 alterations. The primary tumour and the most recent relapse sample were tested for p16/CDKN2A by interphase fluorescence in situ hybridisation. An additional 120 central cartilaginous tumours from different patients were also tested for p16/CDKN2A copy number. The study shows that if an IDH1 mutation were detected in a primary central chondrosarcoma, it is always detected at the time of presentation, and the same mutation is detected in local recurrences and metastatic events. We show that p16/CDKN2A copy number variation occurs subsequent to the IDH1 mutation, and confirm that p16/CDKN2A copy number variation occurs in 75% of high grade central chondrosarcomas, and not in low grade cartilaginous tumours. Finally, p16/CDKN2A copy number variation is seen in both the IDH1 wild-type and mutant cartilaginous central tumours.

Chondromyxoid fibroma management: a single institution experience of 22 cases.

BACKGROUND: Several different strategies have been reported for the treatment of chondromyxoid fibromas, all with variable outcomes and high recurrence rates. METHODS: We report on 22 consecutive cases of chondromyxoid fibromas treated by intralesional curettage, four of which had adjuvant cementation at our institution between 2003 and 2010. We assessed the functional outcome using the Musculoskeletal Tumour Society (MSTS) scoring system. RESULTS: Nine males and 16 females with a mean age of 36.5 years (range 11 to 73) and a mean follow-up of 60.7 months were included in the study. Local recurrence occurred in two patients (9%) within the first 2 years following the index procedure. This was treated by re-curettage only of the residual defect. Two postoperative complications occurred: a superficial wound infection in one patient and a transient deep peroneal nerve neurapraxia in the other. The mean postoperative MSTS score was 96.7%. CONCLUSIONS: Intralesional curettage and cementation is as an effective treatment strategy for chondromyxoid fibromas, providing satisfactory functional results with a low recurrence rate. Careful case selection with stringent clinical and radiographic follow-up is recommended.

Prognostic factors in the operative management of dedifferentiated sacral chordomas.

BACKGROUND: Dedifferentiated chordomas are rare high-grade malignant spinal tumors for which there is minimal information to help guide treatment. OBJECTIVE: To identify prognostic factors associated with increased risk of local recurrence, metastases, and reduced survival in a cohort of patients undergoing sacrectomy for de novo dedifferentiated sacral chordoma. METHODS: Ten patients undergoing sacrectomy for histologically confirmed dedifferentiated chordoma at a specialist center were reviewed. There were 6 male and 4 female patients with a mean age of 66.7 years (range, 57-80 years) and mean follow-up of 36.7 months (range, 3-98 months). Data on prognostic factors were collected. RESULTS: The commonest presenting symptom was lumbar/gluteal pain. Mean duration of preoperative symptoms was 3.6 months (range, 2-7 months). Local recurrence was seen in 7 patients; metastases occurred in 5 patients. After sacrectomy, 7 patients died at a mean of 41 months (range, 3-98 months). Tumor size >10 cm in diameter, amount of dedifferentiation within the conventional chordoma, sacroiliac joint infiltration, and inadequate resection margins were associated with increased risk of recurrence and reduced survival. Surgical approach, cephalad extent of primary tumor, and adjuvant radiotherapy did not affect oncological outcomes. CONCLUSION: Dedifferentiated chordomas are aggressive malignant tumors with a higher risk of local recurrence, metastases, and early mortality than conventional chordomas. Tumor diameter >10 cm, marginal resection, and sacroiliac joint infiltration may be associated with increased risk of local recurrence and mortality. Those with a smaller burden of dedifferentiated disease (<1 cm) within the primary chordoma have a better prognosis. Patients should be counseled about these risks before surgery and should have regular follow-up for the detection of local recurrence and metastases.

Long-term survival of cemented distal femoral endoprostheses with a hydroxyapatite-coated collar: a histological study and a radiographic follow-up.

BACKGROUND: The objective of this study was to examine the degree of osteointegration into a hydroxyapatite-coated collar and relate this finding to aseptic loosening in patients with a distal femoral replacement used to treat primary bone cancer. Our hypothesis was that the implant collar would increase osteointegration and reduce the rate of aseptic implant loosening. METHODS: Sixty-one patients treated with a primary cemented distal femoral prosthesis between 1992 and 2001 were included in this study. The mean duration of follow-up was 8.5 years (range, two to eighteen years). Extracortical bone growth into the grooved hydroxyapatite-coated collar was quantified radiographically. Histological sections through four hydroxyapatite-coated collars and four implants with no collar, retrieved following amputation due to local recurrence or at autopsy at a mean of 3.5 years (range, 1.4 to 6.1 years) after implantation, were evaluated as well. RESULTS: Five (8%) of the implants were revised because of aseptic loosening, 3% of the implants fractured, and 3% were revised because of infection. Six limbs (10%) required amputation because of local tumor recurrence. On radiographs, osteointegration into the collar was seen to have occurred in 70% of the patients and did not correlate with sex, age, diagnosis, or length of time postoperatively. Histological analysis showed mature lamellar bone within the grooves of the hydroxyapatite-coated collar, and bone was observed in direct contact with the hydroxyapatite coating. Extracortical bone failed to make direct contact with the surface of the implants manufactured without a collar. CONCLUSIONS: The use of cemented distal femoral massive bone tumor prostheses with a hydroxyapatite-coated collar located at the shoulder of the implant was followed by a low (8%) rate of revision due to aseptic loosening. The use of hydroxyapatite grooved collars may lead to osteointegration of the implant shoulder (collar) and may reduce the rate of aseptic loosening.

Van Nes rotationplasty as a treatment method for Ewing's sarcoma in a 14-month-old.

INTRODUCTION: In recent years, the rotationplasty procedure has become popular amongst tumour surgeons as an alternative to endoprosthetic replacement or amputation. There are very few documented cases of this technique in young patients with malignancy. PRESENTATION OF CASE: We describe an extremely rare case of Ewing's sarcoma in a 14-month-old boy that involved the entire length of the left femur. At initial presentation, pulmonary metastatic spread had occurred and there was no neurovascular involvement. Complete response to neo-adjuvant chemotherapy was achieved prior to performing the definitive surgical procedure. DISCUSSION: This case highlights the many reconstructive options and difficulties encountered in managing such extremely young patients with aggressive malignant disease. In this case, a complete femoral excision was necessary and various treatment options were explored. These included irradiation and re-implantation, endoprosthetic replacement and manufacturing a custom growing prosthesis. Taking future functional, psychological and social implications into consideration, we performed a total femoral excision and Van Nes rotationplasty of the tibia at our institute. Histological analysis of the tumour resection showed clear tumour margins and at 1 year clinical review, the patient demonstrates good functional outcome with no evidence of disease recurrence. CONCLUSION: Van Nes rotationplasty is a viable reconstructive option in young patients with sarcoma of the femur. We believe this to be the youngest reported case of rotationplasty in current literature.

The effect of femoral head size on functional outcome in primary total hip arthroplasty: a single-blinded randomised controlled trial.

We conducted a prospective single-blinded randomised controlled trial to compare the functional and quality of life outcomes in two groups of patients between 60 and 80 years of age undergoing THR; the first receiving a small head (28-32 mm) metal on polyethylene (MoP) articulation, and the second receiving a large head (44-54 mm) metal on metal (MoM) articulation. We recruited 49 patients and randomised them into one of the two groups (22 MoP and 27 MoM). The results demonstrated no statistical difference in any of the assessed functional outcomes at any follow-up point (p>0.05). There were no dislocations or revisions in either group. Although it has been suggested that large head MoM articulations in THA offer superior stability and function, our results suggest that small head MoP articulations can achieve comparable ROM, function and quality of life at short-term follow-up.

Sensitivity of MDM2 amplification and unexpected multiple faint alphoid 12 (alpha 12 satellite sequences) signals in atypical lipomatous tumor.

This study assessed whether analysis of MDM2 copy number by fluorescence in situ hybridization (FISH) would help distinguish lipomas from atypical lipomatous tumors, otherwise referred to as well-differentiated liposarcomas, using a commercially available MDM2 FISH kit. 227 lipomatous and 201 non-lipomatous tumors were analyzed to assess its sensitivity and specificity. Of 178 mature lipomatous tumors, 86 were classified histologically as lipoma and 92 as atypical lipomatous tumor. Two of the lipomas harboring MDM2 amplification were reclassified as atypical lipomatous tumors. Overall, 13 atypical lipomatous tumors did not reveal MDM2 or CDK4 amplification, although this was reduced to 12 following analysis of multiple slides. Three of these cases revealed very occasional tumor cells harboring high-level MDM2 amplification, two had a dedifferentiated component, and MDM2 amplification was detected when one tumor recurred. The remaining six cases exhibited reactive/inflammatory features and were reclassified as lipomas. The findings indicate that MDM2 amplification is 93.5% sensitive for diagnosing atypical lipomatous tumor. A total of 2 of the 20 dedifferentiated liposarcomas failed to reveal MDM2 amplification. All atypical lipomatous tumors measured >10 cm, two dedifferentiated liposarcoma presented de novo at <10 cm, and ~50% of lipomas measured >10 cm. Spindle cell lipomas, lipoblastomas, hibernomas and pleomorphic liposarcomas did not reveal MDM2 amplification. Of 201 non-lipomatous tumors, eight revealed MDM2 amplification or multiple faint alphoid 12 signals and were reclassified as dedifferentiated liposarcoma. Multiple faint alphoid 12 signals were observed in nine tumors from seven patients, an observation not previously reported on paraffin sections: these included four atypical lipomatous tumors, and three dedifferentiated liposarcomas, one previously diagnosed as a myxofibrosarcoma, all of which also revealed amplification of CDK4, although two lacked MDM2 amplification. MDM2 FISH test is a useful adjunct to histology for distinguishing lipoma from atypical lipomatous tumor. The limitations of molecular genetic tests must be known before introducing them into a clinical service.

Custom endoprosthetic reconstruction for malignant bone disease in the humeral diaphysis.

The optimal reconstructive method following segmental resection of malignant tumours in the humeral diaphysis is unknown as there are no prospective long-term studies comparing biologic with endoprosthetic reconstruction. This is a retrospective review of 13 patients who, between 1995 and 2010, had undergone limb salvage at our institution using a custom-made humeral diaphyseal endoprosthetic replacement following excision of malignant bone disease. There were 9 males and 4 females with a mean age of 35 years at the time of surgery (range: 10 to 78). Mean follow-up was 56.8 months (range: 5 to 148). Cumulative patient survival was 75% at 10 years. Implant survival, with removal of the endoprosthesis or part of it for any reason as an end point, was 47% at 10 years. Seven patients required revision (54%). Complications included metastases in four, aseptic loosening in four, peri-prosthetic fracture in two and local recurrence in two. Mean MSTS and TESS scores were 23 (18 to 27) and 67% (52-80) respectively. Custom-made humeral diaphyseal replacement following resection of malignant bone tumours provided functional results superior to amputation, without an obvious compromise in patient survival. There was a relatively high revision rate for aseptic loosening and peri-prosthetic fracture and patients should be counselled about this preoperatively.

IDH1 and IDH2 mutations are frequent events in central chondrosarcoma and central and periosteal chondromas but not in other mesenchymal tumours.

Somatic mutations in isocitrate dehydrogenase 1 (IDH1) and IDH2 occur in gliomas and acute myeloid leukaemia (AML). Since patients with multiple enchondromas have occasionally been reported to have these conditions, we hypothesized that the same mutations would occur in cartilaginous neoplasms. Approximately 1200 mesenchymal tumours, including 220 cartilaginous tumours, 222 osteosarcomas and another ∼750 bone and soft tissue tumours, were screened for IDH1 R132 mutations, using Sequenom(®) mass spectrometry. Cartilaginous tumours and chondroblastic osteosarcomas, wild-type for IDH1 R132, were analysed for IDH2 (R172, R140) mutations. Validation was performed by capillary sequencing and restriction enzyme digestion. Heterozygous somatic IDH1/IDH2 mutations, which result in the production of a potential oncometabolite, 2-hydroxyglutarate, were only detected in central and periosteal cartilaginous tumours, and were found in at least 56% of these, ∼40% of which were represented by R132C. IDH1 R132H mutations were confirmed by immunoreactivity for this mutant allele. The ratio of IDH1:IDH2 mutation was 10.6 : 1. No IDH2 R140 mutations were detected. Mutations were detected in enchondromas through to conventional central and dedifferentiated chondrosarcomas, in patients with both solitary and multiple neoplasms. No germline mutations were detected. No mutations were detected in peripheral chondrosarcomas and osteochondromas. In conclusion, IDH1 and IDH2 mutations represent the first common genetic abnormalities to be identified in conventional central and periosteal cartilaginous tumours. As in gliomas and AML, the mutations appear to occur early in tumourigenesis. We speculate that a mosaic pattern of IDH-mutation-bearing cells explains the reports of diverse tumours (gliomas, AML, multiple cartilaginous neoplasms, haemangiomas) occurring in the same patient.