The aim of this study was to evaluate the prognostic and therapeutic factors which influence the oncological outcome of parosteal osteosarcoma. A total of 80 patients with a primary parosteal osteosarcoma were included in this retrospective study. There were 51 females and 29 males with a mean age of 29.9 years (11 to 78). The mean follow-up was 11.2 years (1 to 40). Overall survival was 91.8% at five years and 87.8% at ten years. Local recurrence occurred in 14 (17.5%) patients and was associated with intralesional surgery and a large volume of tumour. On histological examination, 80% of the local recurrences were dedifferentiated high-grade tumours. A total of 12 (14.8%) patients developed pulmonary metastases, of whom half had either a dedifferentiated tumour or a local recurrence. Female gender and young age were good prognostic factors. Local recurrence was a poor prognostic factor for survival. Medullary involvement or the use of chemotherapy had no impact on survival. The main goal in treating a parosteal osteosarcoma must be to achieve a wide surgical margin, as inadequate margins are associated with local recurrence. Local recurrence has a significant negative effect on survival, as 80% of the local recurrences are high-grade dedifferentiated tumours, and half of these patients develop metastases. The role of chemotherapy in the treatment of parosteal osteosarcoma is not as obvious as it is in the treatment of conventional osteosarcoma. The mainstay of treatment is wide local excision. Cite this article: Bone Joint J 2015;97-B:1698–1703

The aim of this study was to assess a specific protocol for the treatment of patients with a parosteal osteosarcoma of the distal femur with limb salvage involving hemicortical resection and reconstruction using recycled pasteurised autograft and internal fixation. Between January 2000 and January 2010, 13 patients with a mean age of 26.5 years (17 to 39) underwent this procedure. All the tumours were staged according to Enneking’s criteria: there were eight stage IA tumours and five stage IB tumours. The mean follow-up was 101.6 months (58 to 142), and mean post-operative Musculoskeletal Tumour Society functional score was 88.6% (80% to 100%) at the final follow-up. All the patients had achieved bony union; the mean time to union was 11.2 months (6 to 18). Local recurrence occurred in one patient 27 months post-operatively. No patient had a pulmonary metastasis. A hemicortical procedure for the treatment of a parosteal osteosarcoma is safe and effective. Precise pre-operative planning using MRI is essential in order to define the margins of resection. Although it is a technically demanding procedure, gratifying results make it worthwhile for selected patients. Cite this article: Bone Joint J 2013;95-B:1275–9

AIMS: Parosteal osteosarcoma is a surface osteogenic sarcoma less agressive than conventional osteosarcoma. Most cases begin to show symptoms in the third and fourth decades, and it affects females more often than males. The tumor affected long bones of the limbs, with evident predilection for the distal femur. The aim of this study is to analyze the prognosis of parosteal osteosarcoma, studying its evolution to know its better treatment. Methods: This is a retrospective study of 25 patients with parosteal osteosarcoma. 23 cases have been treated at our institution from 1983 through June 2009, and 2 cases were treated in another center with a follow-up of at least 1 year. We studied the relation between different aspects of these patients: time of evolution, medullar canal invasion, size of tumor, dedifferentiated parosteal osteosarcoma or recurrence, images of RMI and kind of parosteal osteosarcoma, diagnoses with biopsy, relation between surgery and recurrences. Results: We had 4 men and 21 women with a mean age of 30,48 years (13–56).6 cases were dedifferentiated parosteal osteosarcoma. We observed hyperintensity sign in 57,1% cases of dedifferentiated parosteal osteosarcoma. From 18 trephine biopsies, only 9 cases were diagnosed with parosteal osteosarcoma, 8 cases out of 8 incisional biopsies were also diagnosed as parosteal osteosarcoma. There were 5 local recurrences in the first year follow-up. All patients with marginal excision recurred. All patients were alive, free from disease and without metastatic lesions when the study finished. There was relation between the time of evolution of the tumor and the medular canal invasion and the dedifferentiation, but we not found any relation with the tumoral recurrence. The presence of dedifferentiation and the recurrence were more common in bigger tumours. 3 patients were treated with chemotherapy. Conclusions: Parosteal osteosarcoma is a slow-growing tumor with a significantly better prognosis than the conventional osteosarcoma. The diagnosis of parosteal osteosarcoma requires an overall evaluation of the clinical, radiology and pathology findings. The initial study by RMI could help to guide our selective biopsy. First surgical procedure performed is a very important prognosis factor. Wide resection allows a better local control of the disease with fewer recurrences. Time of evolution and canal medullar invasion are more frequent in dedifferentiated parosteal osteosarcoma, but they not affect the rate of recurrence if the initial resection has been appropiate. In our opinion, postoperative chemotherapy should be given to patients with dedifferentiation and canal medular invasion in parosteal osteosarcoma

Forty-one cases of parosteal osteosarcoma were reviewed clinically, radiologically and pathologically. The fibrous and cartilaginous elements of each tumour were graded from I to IV for malignancy. Primary intramedullary involvement was found in one third of Grade I lesions, two-thirds of Grade II and nearly 90% of Grade III lesions. Thirty-five patients with adequate follow-up were also studied and evaluated as to the adequacy of surgical management in relation to the later development of local recurrence or metastasis or both. No metastases were seen from Grade I tumours despite a number of local recurrences. One third of patients with Grade II and half of those with Grade III tumours developed pulmonary metastases and died, all with involvement of the medullary cavity before distant spread. No patients with adequate surgical management developed local recurrence; in those with inadequate treatment there was an 88% local recurrence rate

Introduction: Parosteal osteosarcoma is a rare, mostly low grade tumor arising from the surface of the bone. The aim of the study was to establish risk factors for local recurrence (LR) and death. Method: Retrospective review of a prospectively collected database with complete up-to-date follow up. Results: 63 patients were diagnosed and treated at our centre from 1978 to 2007. The most common site was the femur (37) followed by the tibia (10) and humerus (9). The median size was 7cm (2 – 16). At the time of diagnosis 27 (43%) were low grade, 13 (21%) were low grade but had invaded the medullary canal and 8 (13%) had a high grade component; the data was missing in 15 patients (24%). All patients were operated. LR arose in 11 patients (17.5%) at a mean of 38 months and was related to surgical margins. There were no LR in the 26 wide resections, but the risk of LR was 20% in those with a marginal and 46% in those with an intralesional excision. LR appeared as a higher grade than the primary tumor in 3 patients (27%). 9 (14.3%) patients developed metastases at a median of 22 months (6 – 123). Five patients developed both LR and metastases. Seven patients died from the tumor, 2 patients are alive with metastatic disease. None of the patients with a low grade tumor and wide or marginal margins died of tumor, but 2 patients (18%) operated intralesional died of tumor. Discussion: There was a statistically significant relationship between surgical margins and LR (p< 0.001). All patients with low grade parosteal osteosarcoma operated with wide margins have been cured. LR appeared often in higher grade than the primary tumor. Patients with low grade tumor and intralesional margins had 18% risk to tumor-ralated death

Osteosarcoma arising on the periosteal aspect of bone comprises a biologically heterogeneous group of neoplasm. Parosteal osteosarcoma is a low-grade malignant tumour originates at the surface of bone comprising 3–6% of all osteosarcomas and 2% of primary osseous neoplasms. It is most common in young and middle-aged adults and occurs most frequently on the posterior aspect of the distal femur or tibia. The radiologic appearance is often characterized by a large, lobulated, ossific mass in a juxtacortical position. Cortical thickening without aggressive periosteal reaction can be present. Typically the medullary canal is uninvolved. Wide surgical resection and reconstruction is the treatment of choice. The overall prognosis for patients with this lesion depends on the stage of the tumor at presentation. The prognosis for a Parosteal osteosarcoma is generally excellent. We present an uncommon case of elderly women 70 year-old with a surface osteosarcoma in right femur concomitant with disseminated Breast Carcinoma. The radiological findings showed a juxtacortical mass on the anteromedial aspect of the junction between the mid-third and the distal third of the right femur with areas of new bone formation mimicking Periostal osteosarcoma. We observed a typical Parosteal osteosarcoma when the biopsy was performed. The elected treatment was a wide resection with PTR MUTARS and adjuvant chemotherapy controlling local and systemic diseases. In conclusion, due to the treatment for the juxtacortical osteosarcomas varies with the diagnosis, an accurate evaluation and appropriate management must be executed to have the best outcomes

We have reviewed 20 cases of parosteal osteosarcoma treated by wide local resection and prosthetic replacement and followed up for six to 17 years. Limb function was excellent in 85%. One patient with grade III histological disease developed pulmonary metastases. Four patients had local recurrences, which were related to repeated preliminary biopsies, inappropriate siting of biopsy and vascular encroachment by the tumour. After this mode of treatment, the outcome was not related to medullary invasion by the tumour

Parosteal osteosarcoma is an uncommon tumour. Different methods of surgical treatment have been reported. Aim of this study was to investigate differences in outcome after biological and prosthetic reconstruction. Since August 1969, 28 patients have been treated at our institution. Average age was 26 years, range 15 to 59 years. Patient data was retrospectively reviewed within the prospective database of the Vienna Tumour Registry. Average follow-up was 133.9 months, range 8.4 to 382.6 months. Two patients died of disease 8.4 and 81.4 months after operation, respectively, another patient died due to unrelated causes 330.4 months postoperatively. All surviving patients were followed for a minimum of 3.6 months. Location of the lesion was the distal femur (19), proximal humerus (four), proximal tibia (three), mid-diaphyseal and proximal femur (one each). In 12 patients endoprosthetic reconstruction was indicated. Biological reconstruction was performed in 11 patients. Three patients underwent rotationplasty, two patients were amputated. Eight of 12 patients with endoprostheses have been revised, five have had multiple revisions. Causes for revision were bushing wear (four), aseptic loosening (four), infection (three) and periprosthetic fracture (one). There was no local recurrence in the endoprosthetic group. Two of 11 patients with biological reconstruction underwent revision due to pseudarthrosis and femoral fracture, respectively. There were two cases of local recurrence requiring secondary amputation. Two patients with rotationplasty underwent revision for wound healing disturbance and thrombectomy, respectively. Three patients developed lung metastases, leading to death of disease in two cases of amputation and rotationplasty. One patient with endoprosthetic reconstruction was alive 129.0 months after pulmonary metastasectomy. Functional outcome was satisfactory in all patients; there were no significant differences between patients with endoprosthetic or biological reconstruction. Biological reconstruction showed less revisions compared to endoprostheses, however, exact preoperative planning is required to obtain clear margins of resection

1 . A case of parosteal osteoma with histologically low-grade sarcomatous areas is described.

2. Arteriography revealed abnormal arteries, the histological appearances of which are described.

3. Vascular shunts indicative of low-grade malignancy were also seen.

4. Reasons are given for accepting the view that this lesion is a tumour, originally benign, but liable to the development of low-grade malignancy.

At re-examination of all osteosarcomata recorded in the Swedish Cancer Registry during the years 1958 to 1968, 11 cases of parosteal osteosarcoma were found. No case of so-called periosteal osteosarcoma was identified. The tumours constituted 1.6 per cent of all proved primary malignant bone tumours. The ages of the 11 patients (six women and five men) ranged from 17 to 62 years (average 33 years). The clinical and histopathological findings of this study and of those collected from a review of the literature suggest the occurrence of two different types of parosteal osteosarcoma: the predominant type is originally benign but has a definite malignant potential, causing metastases after long symptom-free intervals; the other type is highly malignant from the beginning. Primary amputation is recommended for the latter category of tumours, and compartmental, radical en bloc resection followed by regular review is recommended for the former

Aims

The purpose of this study was to clarify the clinical behaviour, prognosis, and optimum treatment of dedifferentiated low-grade osteosarcoma (DLOS) diagnosed based on molecular pathology.

Young active patients with malignant tumours arising in the distal fibula, requiring excision, present a challenge to the treating surgeon. Wide local excision is advocated, to achieve clearance, however, disruption of the ankle mortise results and fusion is often required to restore stability. The loss of movement is poorly tolerated in the younger patient and leads to progressive degenerative changes in surrounding joints. Excision of the distal fibula lesion followed by harvesting of the proximal fibula and using this graft to recreate the ankle mortise restores ankle stability and retains ankle movement. Between 1998 and 2007, we have performed this technique on 4 patients. Diagnoses were Ewing’s sarcoma, chondrosarcoma, parosteal osteosarcoma and osteofibrous dysplasia. To date there has been no evidence of distant or local recurrence. One case was complicated by infection, which resolved with radical debridement and antibiotics; the other three fibula grafts survived. Good to excellent results were achieved. We will present the technical aspects of this procedure, with particular reference to the most recent case, performed on a young female patient with parosteal osteosarcoma. We believe this technique provides good oncological and functional results and recommend this treatment option is considered in young active patients requiring distal fibula excisions for sarcoma. Correspondence should be addressed to Major M Butler RAMC, Princess Elizabeth Orthopaedic Centre, Royal Devon and Exeter Hospital, Exeter, Devon

Introduction: Young active patients with malignant tumours arising in the distal fibula, requiring bone and soft tissue excision, present a challenge to the treating surgeon. Wide local excision is advocated, to achieve clearance, however, disruption of the ankle mortise results and fusion is often required to restore stability. The loss of movement is poorly tolerated in the younger patient and leads to progressive degenerative changes in surrounding joints. Method: Excision of the distal fibula lesion followed by rotation of the proximal fibula on its vascular pedicle recreates the ankle mortise with consequent restoration of ankle stability and retaining ankle movement. Results: Between 2000 and 2008, we have performed this technique on four patients, (2F, 2M) mean age 21 (13–33). Diagnoses were that of chondrosarcoma, parosteal osteosarcoma, Ewings sarcoma and osteofibrodysplasia. Follow up at 5 years (18m-8 year) with no evidence of local or distant recurrence. One case was complicated by deep infection requiring surgical debridement and antibiotic therapy. In all cases the fibula grafts survived. Good to excellent functional results were achieved (Toronto Extremity Salvage Scores, mean 88 range 82–94). Discussion: We will present the technical aspects of this procedure with particular reference to the most recent case, performed on a young female patient with parosteal osteosarcoma. We believe this technique provides good oncological and functional results and recommend this treatment option is considered in young active patients required distal fibula excisions for sarcoma

We have carried out prosthetic reconstruction in six patients with malignant or aggressively benign bone tumours of the distal tibia or fibula. The diagnoses were osteosarcoma in four patients, parosteal osteosarcoma in one and recurrent giant-cell tumour in one. Five tumours were in the distal tibia and one in the distal fibula. The mean duration of follow-up was 5.3 years (2.0 to 7.1). Reconstruction was achieved using custom-made, hinged prostheses which replaced the distal tibia and the ankle. The mean range of ankle movement after operation was 31° and the joints were stable. The average functional score according to the system of the International Society of Limb Salvage was 24.2 and five of the patients had a good outcome. Complications occurred in two with wound infection and talar collapse. All patients were free from neoplastic disease at the latest follow-up. Prosthetic reconstruction may be used for the treatment of malignant tumours of the distal tibia and fibula in selected patients

Low-grade surface tumours of bone may theoretically be treated by hemicortical resection, retaining part of the circumference of the cortex. An inlay allograft may be used to reconstruct the defect. Since 1988 we have performed 22 hemicortical procedures in selected patients with low-grade parosteal osteosarcoma (6), peripheral chondrosarcoma (6) and adamantinoma (10). Restricted medullary involvement was not a contraindication for this procedure. There was no evidence of local recurrence or distant metastasis at a mean follow-up of 64 months (27 to 135). Wide resection margins were obtained in 19 patients. All allografts incorporated completely and there were no fractures or infections. Fractures of the remaining hemicortex occurred in six patients and were managed successfully by casts or by osteosynthesis. The functional results were excellent or good in all except one patient. Hemicortical procedures for selected cases of low-grade surface tumours give excellent oncological and functional outcomes. There was complete remodelling and fewer complications when compared with larger intercalary procedures. The surgery is technically demanding but gives good clinical results

Aim. To compare the functional outcome of proximal femoral reconstruction using endoprosthetic replacement and hip arthrodesis using a vascularised fibular graft. Material and Methods. The study included thirty-five patients who had proximal femoral reconstruction following resection of a malignant bone tumour. Patients were divided into 2 groups according to the reconstructive modality used. Group 1 (15 patients) reconstructed by hip arthrodesis using a vascularised fibular graft. Group 2 (20 patients) reconstructed by endoprosthesis. The mean age of group I was 14.9 years (range, 7-25). 8 patients had Ewing's sarcoma, 5 osteogenic sarcoma, and 2 chondrosarcoma. In group 2, the mean age was 35 years (range, 14-61). Eight patients had osteogenic sarcoma, 2 chondrosarcoma, 2 Ewing's sarcoma, 1 lymphoma, 1 MFH, 1 synovial sarcoma, 1 parosteal osteosarcoma, and 4 metastatic carcinomas. Results. In group 1 failure of the fixation occurred in two patients, and deep infection developed in one patient. These patients were managed with revision of internal fixation and debridement respectively. The mean MSTS functional score was 87% (range 70 – 96%) at the time of the latest follow-up (mean = 64 months). The average limb length discrepancy was 2 cm (range 1 to 4). In group 2, two patients developed deep infection, one patient had a dislocation, and one had loosening of the implant with a re-operation rate of 20%. After a mean follow up of 49.1 months, the mean MSTS functional score was 79% (range 60 – 93%). Conclusion. The functional outcome of hip arthrodesis using a vascularized fibular graft is comparable to endoprosthetic replacement after proximal femoral resections. It should be considered as a durable reconstructive modality in children and young active patients with long life expectancy

Background: Bizarre parosteal osteochondromatous proliferation [Nora’s lesion] is a rare tumourous lesion with aggressive growth that affects primarily the small tubular bones of extremities and often recurs after excision. It is often confused with chondrosarcomas, parosteal osteosarcomas and florid reactive periostitis. Materials and Methods: The clinical and pathological findings in eight cases of Nora’s lesion from the Scottish bone tumour registry are presented. Results: There were eight lesions reported in the registry. (5 female & 3 male). Anatomically there was 1 metacarpal lesion, 2 proximal phalanx lesions, 3 middle phalanx lesions and 2 distal phalanx lesions. Age at presentation ranged from 25 – 65 years (mean 41y). The common mode of presentation was pain and swelling for a period of 6 months to 2 years. There was no history of trauma. Two patients were initially misdiagnosed, one as synovial chondromatosis and the other as an osteochondroma. Treatment was in the form of an excision biopsy. The recurrence rate after excision was 62.5%. 60 % of recurrences occurred within 12 mts of excision. One phalangeal lesion recurred twice after excision. There was no distal metastasis. Discussion: Bizarre parosteal osteochondromatous proliferation is histologically composed of bony, chondroid and fibrous proliferation, with a high cellular density and bizarre chondrocytes but is devoid of cellular atypia or necrosis. It is a rare pseudotumorous lesion, with typical clinical, radiographic and histopathology findings similar to those of other benign and malignant tumours. The rarity of this lesion and the high local recurrence rate necessitate an accurate histological diagnosis and complete excision

Objective: To assess whether hemicortical excision and biological reconstruction instead of the conventional wide resection for selected cases of malignant surface tumors, may give adequate oncologic clearance with less morbidity and better function. Methods: From January 2000 to June 2007 a total of 29 malignant surface tumors were managed at our institute. Fifteen of these were treated with hemicortical excision and reconstruction. They consisted of 10 parosteal osteosarcomas, 1 periosteal osteosarcoma, 1 high grade surface osteosarcoma, 1 adamantinoma and 2 surface chondrosarcomas. Nine were in the distal femur, 3 in tibia, 2 in the humerus and 1 in the radius. Four of these were residual/recurrent lesions following earlier intervention. After hemicortical excision with adequate margins the bone defect was reconstructed with allograft/autograft and suitable internal fixation where indicated. Results: Margins were reported free in all cases. There were no infections. Three of five patients who did not have fixation with a plate at index surgery sustained a subsequent fracture which was then reduced and fixed. Follow up duration was from 24 to 90 months. Two patients had isolated soft tissue recurrences. Both underwent re excision and are currently disease free at 36 and 38 months respectively after recurrence. Eleven patients had a maximum possible score of 30 (MSTS functional scoring); other four had a score of 29. None of the cases have developed distant metastasis. Discussion: Early results indicate that in selected cases, hemicortical excision is an oncologically sound procedure. The ability to do a biological reconstruction with bone helps avoid some of the serious complications of a megaprosthetic reconstruction while permitting full active loading of the extremity and near normal function. Internal fixation at index surgery permits early mobilization and minimises the incidence of subsequent fractures

In orthopaedic oncology surgical precision is important and intraoperative imaging is often necessary. CAS may enhance precision and provide continuous 3D imaging without radiation. The goal of this work is to report our experience with CAS. Since 2006 we used CAS (Stryker) in 26 patients with a bone tumour: 11 chondrosarcomas, three osteosarcomas, seven osteochondromas and five miscellaneous. Twelve lesions were located in the femur, six in the pelvis, five in the lower leg and three in the upper extremity. In 18 cases a tumour was excised, in six of these a prosthesis was placed. In eight cases a curettage was done. In 23 cases the navigation was image-based (CT and/or MRI based) and in three cases image-less (no image-preparation necessary preoperatively). CAS was successfully employed in 23 cases. In three cases the procedure was aborted. In two cases, both in the ulna, we were unable to reconstruct the exact dimensions and in one case (image-less) the tracker was to far away from the work-field. There were no complications related to CAS. Mean precision is 0.5 mm. The time CAS takes is about 15 minutes during the procedure (7–60). In the eight curettages it proved helpful. We did not measure radiation time. In the six resections were tumour-prostheses were placed it was really helpful in rotation and length determination. In three of these, image-less navigation was performed (all distal femur). In osteochondroma resections it is helpful in four of seven cases. All surgical margins were adequate in the resections; after curettage, all MRI controls at three months did not show residual tumour. Oncology follow-up is too short yet; there was one local recurrence after two years in a parosteal osteosarcoma. We conclude that CAS can be our navigator in orthopaedic oncology; it is successful in providing precision and continuous 3D imaging. The indication area needs further study