Pathology of intra-articular tumours and tumour-like lesions: pearls, pitfalls and rarities from a general surgical pathology practice.

Intra-articular tumours are uncommonly encountered in routine practice and may present diagnostic challenges to pathologists. Challenges unique to this site include distinction from more common reactive synovial conditions, which are far more common; histologic variability; superimposed reactive changes; and often, lack of provided clinicoradiological context. This article reviews the pathology of the synovial tumours and tumour-like lesions, including diagnostic pearls, pitfalls and rare entities.

A large, locally aggressive giant cell tumour arising from the laryngeal cartilage: A Rare Case Report.

Giant cell tumour is a growth predominantly found in long bones of the body. Giant cell tumour has a rare occurrence in the head and neck. A case of a 31 year old male with no known comorbidities at the ENT Department, Shifa International Hospital, Islamabad presented with anterior neck swelling and hoarseness of voice. Patient was diagnosed as having Giant Cell Tumour of Larynx (GTCL) proven on FNA cytology and post-operative biopsy. GCTL is an uncommon entity with only 45 reported cases in the world.

Epigenetic lockdown of CDKN1A (p21) and CDKN2A (p16) characterises the neoplastic spindle cell component of giant cell tumours of bone.

Giant cell tumour of bone (GCTB) comprises the eponymous osteoclastic multinucleated giant cells eliciting bone lysis, an H3F3A-mutated neoplastic mononucleated fibroblast-like cell population, and H3F3A wild-type mononucleated stromal cells. In this study, we characterised four new cell lines from GCTB. Furthermore, we compared the genome-wide DNA methylation profile of 13 such tumours and three further cell lines with giant cell-rich lesions comprising three H3F3B-mutated chondroblastomas, three USP6-rearranged aneurysmal bone cysts, three non-ossifying fibromas, two hyperparathyroidism-associated brown tumours as well as mesenchymal stem cells, osteoblasts, and osteoclasts. In an unsupervised analysis, we delineated GCTB and chondroblastomas from the other analysed tumour entities. Using comparative methylation analysis, we demonstrated that the methylation pattern of the cell lines approximately equals that of H3F3A-mutated stromal cells in tissue. These patterns more resemble that of osteoblasts than that of mesenchymal stem cells, which argues for the osteoblast as the cell of origin of giant cell tumours of bone. Using enrichment analysis, we detected distinct hypermethylated clusters containing histone and collagen genes as well as target genes of the tumour suppressor p53. We found that the promotor regions of CDKN1A, CDKN2A, and IGFBP3 are methylated more strongly in GCTB than in the other giant cell-containing lesions, mesenchymal stem cells, osteoblasts, and osteoclasts (p < 0.001). This hypermethylation correlates with the lower gene expression at the mRNA level for these three genes in the cell lines, the lack of p16 and p21 in these cell lines, and the lower expression of p16 and p21 in GCTB. Overall, our analysis reveals characteristic DNA methylation patterns of giant cell tumours of bone and chondroblastomas and shows that cell lines of giant cell tumours of bone are a valid model for further analysis of H3F3A-mutated tumour cells. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Outcome of re-operation for local recurrence following pre-operative denosumab administration and curettage for giant cell tumour of bone with difficult joint preservation.

PURPOSE: Denosumab enables joint-sparing surgery (curettage) and surgical downstaging in patients with giant cell tumour of bone (GCTB), where joint preservation is not possible. However, denosumab treatment causes osteosclerosis of the lesion, making it difficult to curet the lesion, leaving the tumour behind, and increasing the local recurrence rate. We performed a three-centre retrospective study to investigate the postoperative local re-recurrence rate, joint preservation status, and functional outcomes of locally recurrent lesions after preoperative denosumab treatment and curettage in patients with difficult joint preservation. METHODS: We included 38 of 142 patients with primary GCTB of the extremities who underwent preoperative denosumab and curettage between 2009 and 2021 with local recurrence. Preoperative denosumab was indicated in patients with minimal residual periarticular and subchondral bones, large extraosseous lesions (Campanacci stage 3), and pathological fractures that made joint preservation difficult. RESULTS: Local re-recurrence occurred in 6 (15.8%) of the 38 patients. In 29 patients who underwent re-curettage, local re-recurrence occurred in six patients (20.7%); however, in nine patients who underwent en bloc resection, no local re-recurrence was observed. The joint preservation rate was 63.2% (24 of 38 patients), with a median Musculoskeletal Tumor Society score of 28 (interquartile range: 26.8-29.0). The median follow-up period after surgery for local recurrence was 63.5 months (interquartile range: 42.5-82.4). CONCLUSION: Since the local re-recurrence rate after re-curettage for local recurrence was low, and the joint preservation rate and affected limb function were good, preoperative denosumab administration may be considered in patients who require downstaging to maintain good limb function (joint preservation).

A novel three-dimensional-printed patient-specific sacral implant for spinopelvic reconstruction in sacral giant cell tumour.

PURPOSE: Spinopelvic reconstruction after sacral tumour resection is one of the most demanding procedures in sacral tumour surgery. The aims of this study were to evaluate the feasibility of spinopelvic reconstruction with 3D-printed prostheses in sacral giant cell tumours and the clinical outcomes and complications at follow-up. METHODS: We retrospectively analyzed ten consecutive patients with giant cell tumors of the sacrum who underwent intralesional nerve-sparing resection with curative intent and custom implant reconstruction between 2016 and 2021. There were four males and six females with a mean age of 40.2 years (range, 25-62 years) at surgery. A computer-aided-design implant was prepared using 3D printing technology that was both matched to the bone defect and biomechanically evaluated. A 3D-printed surgical guide was used to replicate the resection procedure as planned. We analyzed operational outcomes, oncological outcomes, functional outcomes, complications, and prosthetic outcomes. Pain at rest was assessed according to a 10-cm VAS score. The results of functional improvement were evaluated using the MSTS-93 score at the final follow-up. RESULTS: All patients were observed for 26 to 61 months, with an average follow-up of 43.8 months. No deep infection or prosthetic structural failure occurred in this study. A total of 80% of patients had good neurological function and normal urinary, bowel, and ambulatory functions. The mean MSTS score was 24.1 (range, 22-26). The mean VAS score was 2 (range 0 to 2). Delayed wound healing occurred in three patients, and the wounds healed after debridement. One case had local recurrence and survived tumour-free after resection of the recurrent lesion. An aseptic loosening was found in a patient that did not require secondary surgery. By radiographical assessments, we found that 90% of implants were well osseointegrated at the final follow-up examination. CONCLUSIONS: The 3D-printed sacral implants might provide a promising strategy for spinopelvic reconstruction in sacral giant cell tumours undergoing intralesional nerve-sparing surgery with satisfactory clinical outcomes, osseointegration, and excellent durability.

Cytodiagnosis of giant cell tumour presenting at unusual age and site with review of literature.

Giant cell tumour (GCT), also known as osteoclastoma, is an osteolytic tumour. It involves the epiphyseal and metaphyseal regions of long bones in adults. On rare occasions, these may occur in paediatric patients, and may involve uncommon locations such as the sternum, pelvis and, particularly infrequently, rib bones. We present a rare case of GCT in the rib of a child, diagnosed on fine needle aspiration.

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.

Clinicopathologic and molecular features of denosumab-treated giant cell tumour of bone (GCTB): Analysis of 21 cases.

GCTB is an osteolytic, locally-aggressive, rarely-metastasizing tumour, characterized by abundance of osteoclast-like giant cells, induced by neoplastic mononuclear cells expressing high-levels of the receptor activator of nuclear factor Kappa-B ligand (RANKL), a mediator of osteoclast activation. Although the mainstay of treatment is complete tumour removal with preservation of bone, therapy with denosumab, an inhibitor of RANKL, has been introduced for selected cases. OBJECTIVES: Denosumab-treated GCTB (DT-GCTB) was reported to show a wide spectrum of histological changes such as depletion of osteoclast-like giant cells and intralesional bone deposition, which may lead to diagnostic difficulties. We investigated clinicopathologic and molecular features of DT-GCTB, matched with pre-therapy samples. PARTICIPANTS: 21 cases were included (13 females, 8 males), aged 15 to 64 (median, 30 years). RESULTS: DT-GCTB showed development of sclerotic neocortex and varying degrees of osteosclerosis radiographically. Marked depletion of giant cells, different degree of ossification, fibrosis, and proliferation of mononuclear cells was observed. Staining for H3.3G34W was positive in mononuclear cells in 19 cases (90.5%), while one negative case was positive for H3.3G34V. H3F3A G34W mutation was confirmed in 17 of 19 cases (89.5%), corresponding to nuclear staining with H3.3 G34W antibody. G34L mutation was detected in one G34W negative case, in which H3.3 G34V nuclear positive staining was observed, possibly due to cross-reaction. CONCLUSIONS: Post-therapy tumours still exhibit a similar mutation profile, while significantly differing from classic GCTB morphologically. Correlation with history of denosumab administration, awareness of features of DT-GCTB, IHC and molecular studies for histone H3 mutations are important in its assessment.

Computerised tomography features of giant cell tumour of the knee are associated with local recurrence after extended curettage.

BACKGROUND: Extended curettage has increasingly become the preferred treatment for giant cell tumour of bone (GCTB), but the high recurrence rate after curettage poses a major challenge for orthopaedic surgeons. Computed tomography (CT) is valuable in the evaluation of GCTB. Our aim was to identify specific features of GCTB around the knee in pre-operative CT images that might have prognostic value for local recurrence. METHODS: We retrospectively analyzed data from 124 patients with primary GCTB around the knee who underwent extended curettage from 2010 through 2019. We collected demographic, clinical, and therapeutic data along with several CT-derived tumour characteristics. CT-derived tumor characteristics included tumour size, the distance between the tumour edge and articular surface (DTA), and destruction of posterior cortical bone (DPC). Akaike information criterion (AIC) was used to select which variables to enter into multivariate logistic regression models and to determine significant factors affecting recurrence. RESULTS: The total recurrence rate was 21.0% (26/124), and the average follow-up time was 69.5 ± 31.2 months (24-127 months). Age, DTA (< 2 mm), and DPC were significantly related to recurrence, as determined by multivariate logistic regression. The C-index of the final model was 0.79 (95% CI: 0.71 to 0.88), representing a good model for predicting recurrence. CONCLUSION: Identifying certain features of GCTB around the knee on CT has prognostic value for patients treated with extended curettage. A three-factor model predicts tumour recurrence well after extended curettage.

Diagnostic Utility of Genetic and Immunohistochemical H3-3A Mutation Analysis in Giant Cell Tumour of Bone.

To validate the reliability and implementation of an objective diagnostic method for giant cell tumour of bone (GCTB). H3-3A gene mutation testing was performed using two different methods, Sanger sequencing and immunohistochemical (IHC) assays. A total of 214 patients, including 120 with GCTB and 94 with other giant cell-rich bone lesions, participated in the study. Sanger sequencing and IHC with anti-histone H3.3 G34W and G34V antibodies were performed on formalin-fixed, paraffin-embedded tissues, which were previously decalcified in EDTA if needed. The sensitivity and specificity of the molecular method was 100% (95% CI: 96.97-100%) and 100% (95% CI: 96.15-100%), respectively. The sensitivity and specificity of IHC was 94.32% (95% CI: 87.24-98.13%) and 100% (95% CI: 93.94-100.0%), respectively. P.G35 mutations were discovered in 2/9 (22.2%) secondary malignant GCTBs and 9/13 (69.2%) GCTB after denosumab treatment. We confirmed in a large series of patients that evaluation of H3-3A mutational status using direct sequencing is a reliable tool for diagnosing GCTB, and it should be incorporated into the diagnostic algorithm. Additionally, we discovered IHC can be used as a screening tool. Proper tissue processing and decalcification are necessary. The presence of the H3-3A mutation did not exclude malignant GCTB. Denosumab did not eradicate the neoplastic cell population of GCTB.

Malignant Transformation of Giant Cell Tumour of Bone: A Review of Literature and the Experience of a Referral Centre.

Giant cell tumour of bone (GCTB) is a benign, locally aggressive primary bone neoplasm that represents 5% of all bone tumours. The principal treatment approach is surgery. Although generally GCTB is considered only a locally aggressive disease, it can metastasise, and lung metastases occur in 1-9% of patients. To date, only the use of denosumab has been approved as medical treatment for GCTB. Even more rarely, GCTB undergoes sarcomatous transformation into a malignant tumour (4% of all GCTB), but history of this malignant transformation is unclear and unpredictable. Considering the rarity of the event, the data in the literature are few. In this review, we summarise published data of GCTB malignant transformation and we analyse three cases of malignant transformation of GCTB, evaluating histopathology, genetics, and radiological aspects. Despite the rarity of this event, we conclude that a strict follow up is recommended to detect early malignant transformation.

Aberrant sphingomyelin 31P-NMR signatures in giant cell tumour of bone.

An understanding of the biochemistry of the giant cell tumour of bone (GCTB) provides an opportunity for the development of prognostic markers and identification of therapeutic targets. Based on metabolomic analysis, we proposed glycerophospholipid metabolism as the altered pathway in GCTB., The objective of this study was to identify these altered metabolites. Using phosphorus-31 nuclear magnetic resonance spectroscopy (31P-NMR), sphingomyelin was determined to be the most dysregulated phospholipid in tissue samples from six patients with GCTB. Enzymes related to its biosynthesis and hydrolysis were examined using immunodetection techniques. High expression of sphingomyelin synthases 1 and 2, but low expression of neutral sphingomyelinase 2 (nSMase2) was found in GCTB tissues compared to non-neoplastic bone tissues. Sphingomyelin/ceramide biosynthesis is dysregulated in GCTB due to alterations in the expression of SMS1, SMS2, and nSMase2.

H3F3A-mutated giant cell tumour of bone without giant cells-clinical presentation, radiology and histology of three cases.

AIMS: Giant cell tumour of bone (GCTB) is histologically defined as a lesion containing reactive giant cells and a neoplastic mononuclear cell population; in up to 92% of cases, GCTB is characterised by a specific mutation of the histone gene H3F3A. The cellular composition ranges from giant-cell-rich to giant-cell-poor. The diagnosis of GCTB can be challenging, and several other lesions need to be excluded, e.g. aneurysmal bone cysts, non-ossifying fibromas, chondroblastomas, brown tumours, and giant-cell-rich osteosarcomas. Our aim was to analyse the clinical history, imaging, molecular pathology and histology of three H3F3A-mutated bone tumours without detectable giant cells. None of the patients received denosumab therapy. METHODS AND RESULTS: Diagnostic material was obtained by curettage or resection and/or biopsy. Common histomorphological features of all three reported lesions were fibrocytic, oval cells in a background of osteoid and an absence of multinuclear giant cells as confirmed with CD68 immunohistochemistry. We used immunohistochemistry and Sanger sequencing to demonstrate positivity for the H3.3 p.G34W mutation. Differential diagnoses were systematically excluded on the basis of histomorphology, immunohistochemistry, and fluorescence in-situ hybridisation. The imaging (radiography, computed tomography, and magnetic resonance imaging) for all three cases is presented and discussed. CONCLUSIONS: We believe that these GCTBs without giant cells expand one end of the heterogeneous range of GCTB. Because of the lack of giant cells, correct diagnosis of GCTB is challenging or even impossible on histological grounds alone. In these cases, detection of the characteristic H3F3A mutation (G34W-specific antibody RM263 or sequencing) is extremely helpful for diagnosing those lesions without giant cells as giant cell tumours of bone.

Drivers underpinning the malignant transformation of giant cell tumour of bone.

The rare benign giant cell tumour of bone (GCTB) is defined by an almost unique mutation in the H3.3 family of histone genes H3-3A or H3-3B; however, the same mutation is occasionally found in primary malignant bone tumours which share many features with the benign variant. Moreover, lung metastases can occur despite the absence of malignant histological features in either the primary or metastatic lesions. Herein we investigated the genetic events of 17 GCTBs including benign and malignant variants and the methylation profiles of 122 bone tumour samples including GCTBs. Benign GCTBs possessed few somatic alterations and no other known drivers besides the H3.3 mutation, whereas all malignant tumours harboured at least one additional driver mutation and exhibited genomic features resembling osteosarcomas, including high mutational burden, additional driver event(s), and a high degree of aneuploidy. The H3.3 mutation was found to predate the development of aneuploidy. In contrast to osteosarcomas, malignant H3.3-mutated tumours were enriched for a variety of alterations involving TERT, other than amplification, suggesting telomere dysfunction in the transformation of benign to malignant GCTB. DNA sequencing of the benign metastasising GCTB revealed no additional driver alterations; polyclonal seeding in the lung was identified, implying that the metastatic lesions represent an embolic event. Unsupervised clustering of DNA methylation profiles revealed that malignant H3.3-mutated tumours are distinct from their benign counterpart, and other bone tumours. Differential methylation analysis identified CCND1, encoding cyclin D1, as a plausible cancer driver gene in these tumours because hypermethylation of the CCND1 promoter was specific for GCTBs. We report here the genomic and methylation patterns underlying the rare clinical phenomena of benign metastasising and malignant transformation of GCTB and show how the combination of genomic and epigenomic findings could potentially distinguish benign from malignant GCTBs, thereby predicting aggressive behaviour in challenging diagnostic cases. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.

The use of denosumab in the setting of acute pathological fracture through giant cell tumour of bone.

BACKGROUND: Denosumab (XgevaTM) is a fully human antibody to RANK-Ligand, an important signal mediator in the pathogenesis of giant cell tumour of bone (GCTB). The use of denosumab in the treatment of GCTB has changed the way in which these tumours are managed over the past years. CASE PRESENTATION: Described is the case of an acute fracture through a GCTB of the distal radius of a fit and well 32-year-old, non-smoking, female patient following a simple fall onto her outstretched, dominant hand. The aim was to enable joint sparing management for the patient, as opposed to an acute fusion procedure of the carpus. The patient underwent percutaneous k-wire fixation with application of plaster and immediate commencement with denosumab to halt the activity of the GCTB. Bone healing was rapid; plaster and k-wires were removed after 6 weeks. At 6 months denosumab, was ceased and an open curettage and grafting procedure of the tumour bed was undertaken (using MIIG X3, Wright Medical, aqueous calcium sulphate as graft material). CONCLUSIONS: The use of denosumab in the acute setting of pathological fracture through giant cell tumour of bone allowing joint salvage has not been previously described. The treatment was well tolerated and functional outcomes are excellent, with very promising 4-year follow-up. This novel approach may allow for more joint sparing strategies in the future for other patients in this difficult situation. Further cases will need to be gathered to establish this technique as a suitable treatment pathway.

Giant cell reparative granuloma of the phalanx in a violinist.

Giant cell reparative granuloma (GCRG) is a rare, pseudotumoural intraosseous lesion, considered a reactive injury after repeated trauma. Reactive lesions and benign bone tumours may show aggressive clinical and radiographic findings. Differential diagnosis must be performed in order to offer suitable treatment to the patient. Excisional biopsy and curettage of the lesion are the preferred methods of treatment. We present the first case of a GCRG of the distal phalanx of the left little finger in a professional violinist.

The impact of curettage technique on local control in giant cell tumour of bone.

INTRODUCTION: Although consensus has been reached regarding the main aspects of intralesional surgery for giant cell tumour of the bone (GCTB), debates continue about the most effective combination of local adjuvants. The purpose of study was to analyze the previous experience and determine the most effective curettage approach for GCTB. METHODS: We summarized the findings from 89 papers published from 1962 to 2020 related to this subject. Database consisted of 137 treated groups that included 6441 patients who underwent different curettage techniques without pre-operative administration of bisphosphonates or RANKL inhibitors. RESULTS: Recurrence rates after simple curettage ranged between 27 and 82% with a median value at 47%. The use of one or two local adjuvants reduced the incidence of recurrences approximately by 50% when compared with simple curettage. High-speed burring combined with chemical adjuvants or followed by poly(methyl methacrylate) cementation with or without bone grafting further improved the local control leading to good and excellent results; however, these were not documented in all studies. Simultaneous use of burring, chemical adjuvants, and cementation, which we named here as combined curettage, allowed to down local relapses to the range of 0-26%, with a median at 11%. Oncologic outcomes after combined curettage are significantly better when compared with simple curettage (p < 0.0001) and other variants of enhancement (p = 0.001). CONCLUSIONS: Combined curettage appears to provide the most potent and comprehensive impact on residual tumour cells located in risk zones. This approach should be considered for locally advanced tumours when function-preserving surgery is planned. Additional comparative studies are required to define the optimal curettage enhancement for each individual patient.

Pulmonary metastasis of giant cell tumour: a retrospective study of three hundred and ten cases.

BACKGROUND: Giant cell tumour (GCT) is an invasive benign bone tumour, and the incidence of pulmonary metastasis is rare. We are aiming to analyze risk factors of pulmonary metastasis and clinical prognosis for giant cell tumour patients with pulmonary metastasis. METHOD: We performed a retrospective study of 310 patients with GCT between December 2004 and December 2016. Risk factors of pulmonary metastasis were analyzed by univariate and multivariate logistic regression analysis. Then, the influence of risk factors of overall LR (local recurrence), recurrent tumor at presentation, LR after our therapy, and with soft tissue mass on the pulmonary metastasis-free survival rates was analyzed. RESULTS: The mean follow-up of the present cohort was 45.6 ± 35.3 months (median, 36.6 months; range, 6.1-193.4 months). Eighteen (5.8%) of 310 patients developed pulmonary metastasis. The average interval from surgery of primary tumour to detection of pulmonary metastasis was 15 months. Multivariate logistic regression analysis showed overall local recurrence was the independent risk factor of developing pulmonary metastasis. Among 18 patients with pulmonary metastasis, sixteen cases had history of local recurrence (88.9%, 16/18), including eleven (68.8%, 11/16) with local recurrence at presentation before receiving our therapy and seven (43.8%, 7/16) with local recurrence after receiving treatment in our hospital. Time to local recurrence had obvious difference between patients with and without pulmonary metastasis. Patients with pulmonary metastasis were prone to recur earlier. Furthermore, overall local recurrence, local recurrence after our therapy, recurrent tumor at presentation, and tumour with a soft tissue mass showed statistical differences in the pulmonary metastasis-free survival rates. CONCLUSIONS: Giant cell tumour patients with soft tissue mass and overall local recurrence are prone to develop pulmonary metastasis. Although giant cell tumour is a benign tumor, more attention should be paid to the problem of pulmonary metastatic lesions, and chest CT scan should be recommended during follow-up.

Extended curettage versus en bloc resection for the treatment of grade 3 giant cell tumour of the knee with pathologic fracture: a retrospective study.

PURPOSE: For the treatment of giant cell tumour of the bone (GCTB) around the knee, preserving the native joint confers advantages over scarifying it. But, there is a controversy about the efficacy of intralesional curettage versus en bloc resection for treatment of such lesions. In this study, we compared local recurrence, functional outcomes, and complications of extended curettage and en bloc resection in these lesions. METHODS: Patients with grade 3 GCTB of the distal femur or proximal tibia who were presented with a pathologic fracture and treated with either en bloc resection (n = 22) or extended curettage (n = 20) were included. The mean follow-up of the patients was 6.4 ± 1.9 years in the resection group and 5.5 ± 2.4 years in the extended curettage group. The primary outcome was a local recurrence. Secondary outcomes were limb function evaluated by the Musculoskeletal Tumor Society (MSTS) score and rate of complications. RESULTS: Local recurrence was seen in four (20%) patients of the curettage group and three (13.7%) patients of the resection group (P = 0.69). The mean MSTS score was 24 ± 1.9 in the resection group and 26.5 ± 1.3 in the curettage group (P < 0.001). The number of complications was not significantly different between the two study groups (P = 0.49). However, the number of complications that required revision surgery was significantly more in the resection group (P = 0.049). CONCLUSION: In grade 3 GCTB around the knee with pathologic fracture, extended curettage results in comparable oncologic outcomes to en bloc resection, while providing better function and a lower rate of revision.

[Medial femoral condyle free flap for reconstruction of carpometacarpal bone defect after giant cell tumour of tendon synovial sheath resection]. / Transfert osseux libre de condyle fémoral médial pour la reconstruction d'une perte de substance osseuse carpo-métacarpienne après résection d'une tumeur à cellule géante des gaines synoviale.

We report the case of a 23-year-old patient treated for a large giant cell tumour of the synovial sheaths of the ulnar edge of the hand and wrist invading the triquetrum, the hamatum, the ulnar part of the capitate as well as the bases of the 3rd, 4th and 5th metacarpals and the floor of the Guyon's canal and the carpal tunnel. A monobloc resection was performed in a healthy margin ; the loss of bone substance was 7×3.5cm. We performed a bone reconstruction using a cortico-cancellous medial femoral condyle free flap of 8×4cm. Postoperative follow-up was uneventful and bone consolidation was achieved at 2,5 months postoperatively. The cortico-cancellous medial femoral condyle free flap is an interesting option for treating small and medium size bone loss in the hand and wrist. Its use in its pure bone form or in its chimeric form with muscle, cartilage or skin opens up a wide range of choices for the reconstructive surgeon.