Parosteal Osteosarcoma: A Benign-Looking Tumour, Amenable to a Variety of Surgical Reconstruction.

Osteosarcoma arising from cortical surface is classified into parosteal, periosteal and high-grade surface osteosarcoma. Along the spectrum, parosteal osteosarcoma occupies the well-differentiated end. It is a relatively rare disease entity, comprised only 4% of all osteosarcomas and barely reported in the literature. The objective of this study is to describe cases of parosteal osteosarcoma as well as a variety of treatment options amenable to such entity. Six cases of parosteal osteosarcoma were identified based on histopathological reports in a tertiary referral hospital in Jakarta, Indonesia between January 2001 and December 2019. The mean age was 29.8 years old; four of them (66.7%) were male. Distal end of femur was the most commonly involved bone (five cases, 83.3%). The patients were treated with wide excision followed by several different reconstruction methods: replacement with endoprosthesis, extracorporeal irradiation, knee arthrodesis, or prophylactic fixation. One of our patients presented with dedifferentiated component, and therefore was treated by limb ablation. While two cases died of pulmonary metastasis, other patients reported fair to excellent functional outcome.

The prognostic and therapeutic factors which influence the oncological outcome of parosteal osteosarcoma.

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.

A comparison of intramedullary and juxtacortical low-grade osteogenic sarcoma.

UNLABELLED: While low-grade juxtacortical and low-grade intramedullary osteogenic sarcomas are histologically indistinguishable, they have been studied as separate entities. We retrospectively reviewed the clinical, radiographic, histologic features and treatment of 59 patients treated surgically to compare the rate of local recurrence, grade progression, and survival between low-grade intramedullary and low-grade juxtacortical osteogenic sarcoma. Forty-five (76%) patients were treated for low-grade juxtacortical osteogenic sarcoma and 14 (24%) were treated for low-grade intramedullary osteogenic sarcoma. Local recurrence rates of 7% were similar for both groups studied. The rate of distant metastases was also similar for both groups. . The rate of dedifferentiation for the entire group was 29%. Dedifferentiated lesions were treated with adjuvant chemotherapy in 16 of 17 cases. Recurrence preceded dedifferentiation in four cases. Five-year survival was over 90% in both groups. Low-grade intramedullary and low-grade juxtacortical osteogenic sarcoma were clinically indistinguishable with identical rates of local recurrence, distant metastases, dedifferentiation, and survival. LEVEL OF EVIDENCE: Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Dedifferentiated parosteal osteosarcoma with well-differentiated metastases.

Metastases of dedifferentiated sarcoma usually contain a dedifferentiated component. We report a rare case of dedifferentiated parosteal osteosarcoma (dd-POS) with well-differentiated multiple metastases in a 65-year-old woman with a painful firm mass on her thigh. Radiological examination revealed that the mass arose from the surface of her femur without medullary involvement. Multiple intramuscular metastases were detected in her lower leg on MR imaging. Small subcutaneous palpable masses were identified on her left lower leg, buttock, chest wall and head. An open biopsy and above-the-knee amputation were performed, and the mass on her femur was diagnosed as a dd-POS. However, histological examination on the subcutaneous lesions in her lower leg, buttock and head showed low-grade conventional POS without dedifferentiated components. To the best of our knowledge, this is the first report of a dd-POS with multiple metastases that do not contain any dedifferentiated components.

Pediatric surface osteosarcoma: clinical, pathologic, and radiologic features.

BACKGROUND: Osteosarcoma (OS) arising from the surface of bone is far less common than its intramedullary counterpart. Although surface OSs share some radiographic and clinical features, they can be divided into three distinct histologic subtypes. PROCEDURE: We reviewed the clinical, radiographic, and pathologic features of 14 cases of pediatric surface OS treated at St. Jude Children's Research Hospital between 1970 and 2003. RESULTS: Seven patients had parosteal, five had periosteal, and two had high-grade surface OS. The median age at diagnosis was 16.2 years (range, 13.6-18.5 years). Nine patients were male; 11 were Caucasian. None had metastatic disease at diagnosis. Primary tumor sites included distal femur (n = 6), mid to proximal femur (n = 4), and mid to proximal tibia (n = 4). All 14 patients were treated with surgery, and 7 (1 with parosteal, 4 with periosteal, 2 with high-grade tumors) received chemotherapy. One patient experienced pulmonary metastasis of periosteal OS 16 months and 43 months after diagnosis; long-term disease-free survival followed resection of the metastatic tumors. Twelve patients remained alive and disease-free a median of 10 years (range, 1.5-25.4 years) after diagnosis. One patient died of high-grade surface OS 1.8 years after diagnosis, and one patient with periosteal OS died of gastric cancer 18.2 years after diagnosis of OS. CONCLUSIONS: The histologic grade predicts the clinical behavior of pediatric surface OS. Complete resection is the treatment of choice regardless of tumor subtype. Whereas chemotherapy is not indicated for parosteal OS, its role in periosteal OS remains controversial.

Dedifferentiated parosteal osteosarcoma: the experience of the Rizzoli Institute.

BACKGROUND: Dedifferentiated parosteal osteosarcoma (DPOS) is a variant of osteosarcoma in which a high-grade sarcoma coexists with a conventional parosteal osteosarcoma (c-POS), either at presentation (synchronous type) or at the time of recurrence (metachronous type). Only approximately 60 patients have been reported in the literature. The objective of this study was to analyze the clinicopathologic and radiographic features of a relatively large number of patients with DPOS in an attempt to define further the histologic and biologic behavior of this rare entity. METHODS: In a series of 120 patients with parosteal osteosarcoma who were seen at the Rizzoli Institute from 1958 to 2000, the authors identified 29 patients who were diagnosed with DPOS. The authors reviewed the clinical and radiologic features, histologic sections, treatments, and outcomes in this group of patients with DPOS. RESULTS: Twelve patients were male, and 17 patients were female. The patients ranged in age from 15 years to 65 yrs (average, 36 years; median, 32 years). One tumor involved the scapula, one involved the ilium, and another involved the skull. All 26 of the other tumors were located in the long bones (14 in the femur, 5 in the humerus, 3 in the tibia, 3 in the fibula, and 1 in the ulna). In 18 patients, radiographic areas of lucency were seen within an otherwise sclerotic lesion. Histologically, the dedifferentiated component was high-grade osteoblastic osteosarcoma in 14 patients, fibroblastic osteosarcoma in 10 patients, giant cell-rich osteosarcoma in 3 patients, and chondroblastic osteosarcoma in 2 patients. All tumors were Stage IIB, and invasion of the medullary canal was detected in 19 patients (65%). Twenty-eight patients underwent surgery, and 18 of those patients received chemotherapy (5 patients received neoadjuvant chemotherapy, and 13 patients received adjuvant). Nine patients were dead and 20 patients were alive (average follow-up, 107 months; range, from 3 months to 36 years) at the last follow-up. Of the nine patients who died, one patient received no treatment, five patients underwent surgery (with three patients achieving adequate margins) in combination with chemotherapy, and three patients underwent surgery only (with adequate margins achieved). Of the 20 patients who remained alive, 13 patients underwent surgery (with 10 patients achieving adequate margins) in combination with chemotherapy, whereas 7 patients underwent surgery only (all with adequate margins). Seven of the nine patients who died had widespread metastases. One patient died of causes unrelated to the tumor, and another patient died shortly after undergoing resection of a lesion in the skull. CONCLUSIONS: Dedifferentiation occurred in approximately 24% of patients with c-POS. The prognosis for patients with DPOS was better than the prognosis for patients with dedifferentiated central and dedifferentiated peripheral chondrosarcoma.

The role of imaging modalities in the diagnosis of primary dedifferentiated parosteal osteosarcoma.

Dedifferentiated parosteal osteosarcoma (dd-POS) is defined as high-grade sarcomatous components coexisting with low-grade POS components. With regard to the histological diagnosis of dd-POS, the sampling of a small area of dedifferentiation through the densely mineralized POS can be a problem. In this situation, imaging is important to identify the area with the highest possibility of dedifferentiation. We report a patient in whom dedifferentiation was shown by computed tomography (CT) and magnetic resonance imaging (MRI). CT revealed a radiolucency in a highly mineralized area. T2-Weighted MRI showed a relatively high signal intensity, corresponding to the radiolucency, surrounded by a very low signal intensity area. Furthermore, gadolinium-enhanced T1-weighted MRI showed marked enhancement. Based on these imaging techniques, the condition was diagnosed as most likely to be a dd-POS, although a representative sample was not accessible by incisional biopsy. Neoadjuvant chemotherapy was administered, followed by wide resection and adjuvant chemotherapy. Four years after the surgery, partial lobulectomy was required because of a pulmonary metastasis. Three years after the second surgery, the patient remained well without evidence of metastases. Based on the initial diagnosis and, consequently, the optimal treatment of combined chemotherapy and wide resection, our patient showed a good clinical outcome.

Dedifferentiated parosteal osteosarcoma with high-grade osteoclast-rich osteogenic sarcoma at presentation.

We report a case of a 32-year-old woman who presented with parosteal osteosarcoma of the distal femur with simultaneous dedifferentiation to a high-grade osteoclast-rich osteogenic sarcoma. This pattern of dedifferentiation is rare, particularly at the time of presentation. We are aware of three other somewhat comparable cases in the literature; however, none is quite similar to our case.

[Microwave heating and neoadjuvant chemotherapy for malignant bone tumor].

Limb salvage is widely used but has different disadvantages. Attempting to establish a new limb conservative procedure, we treate patients with malignant bone tumor by intraoperative microwave heating on tumor bearing bone in place and neoadjvant chemotherapy. The tumors were localized at distal femur in 16, proximal tibia in 5, femur shaft in 2, and illia in 2. Pathological diagnosis showed osteosarcoma in 16 patents, parosteoal osteosarcoma in 4, chondrosarcoma in 3, and leiomyosarcoma in 2. The stage of tumor was II b in 18 patients, II a in 6, and III b in 3. Operative technique was wide resection for tumor in soft tissue, protecting the surrounding tissue from heat injury by copper net, and cheating tumor bone at 50 C for 15 minutes. Follow-up varied from 4 to 180 months (mean 57 months). The 5-, 10-years surviral rates were 70.19% and 54.83% respectively. Functional results of 21 patients were > 15 points by Enneking system. The advantages of the method and keeping the shape and continuity of the tumor bearing bone without osteotomy and internal fixation, controlling the time and temperature of heating treatment easily, benefiting for bone remodeling of heated bone. The indications, complications, and surgical procedure of this method were discussed in detail.

Conventional and dedifferentiated parosteal osteosarcoma. Diagnosis, treatment, and outcome.

BACKGROUND: Dedifferentiated parosteal osteosarcoma (dd-POS) designates high grade transformation, of conventional low grade parosteal osteosarcoma (c-POS). The paradigm of preoperative diagnosis, neoadjuvant chemotherapy, and wide local excision has not been adequately evaluated for dd-POS, as it has been for conventional high grade intramedullary osteosarcoma. METHODS: A retrospective review was conducted of 28 patients treated at the authors' institution between January 1980 and December 1992 for an osteosarcoma arising on the surface of the bone diagnosed as either c-POS or dd-POS. The clinicopathologic features, diagnosis, treatment, and patient outcome were analyzed. RESULTS: A dedifferentiated component was identified in 12 of 28 tumors (43%). Neither the presence of radiolucencies (77% in c-POS and 100% in dd-POS, P = 0.06) nor medullary invasion (42% in c-POS and 50% in dd-POS, P = 0.28) distinguished dd-POS from c-POS. However, all patients who presented with focal hypervascularity on an arteriogram defined the high grade component of dd-POS that was confirmed by selective needle biopsy. This differed significantly (P = 0.00003) from c-POS. None of the patients with c-POS died of the disease (median survival duration, 77 months; range, 16-152 months). Six patients (35%) developed a local recurrence, but five were treated successfully with further surgery. In the dd-POS group, 7 of the 12 patients died of the disease. Ten patients with dd-POS received preoperative chemotherapy (IA cis-diamminedichloroplatinum, IV doxorubicin), and a good response (> 90% necrosis of high grade component) was observed in four. Among patients whose disease was localized, continuous disease free survival was prolonged significantly (P = 0.03) in patients with a good response (median, 75 months) compared with those who responded poorly (median, 13 months). Five patients remained continuously disease free (median, 66 months, range, 29-95 months). CONCLUSIONS: Wide surgical excision alone is adequate treatment for patients with c-POS. Recognition of dedifferentiated areas with angiography and percutaneous biopsy of hypervascular areas should prompt the administration of chemotherapy and wide local excision to optimize patient outcome.

Limb salvage in primary malignant bone tumors by intraoperative microwave heat treatment.

OBJECTIVE: To use intraoperative microwave heat for the treatment of tumor-bearing bone in situ for limb-salvage in primary malignant bone tumor. PATIENTS AND METHODS: Twenty-five patients with malignant bone tumor received surgical protocol for limb-salvage by wide exposure and intraoperative microwave heat treatment of tumor bone in situ. The tumor was localized at distal femur in 16 patients, proximal tibia in 5, shaft of femur in 2, and illia in 2. RESULTS: The pathological diagnosis revealed osteosarcoma in 16 patients, parosteal osteosarcoma in 4, chondrosarcoma in 3, and leiomyosarcoma in 2. The stage of tumor was classified into IIB in 16 patients, IIA in 6, and IIIB in 3. The operative technique was wide exposure for tumor in soft tissues, protecting the surrounding normal tissue from heat injury by copper mesh, and heating tumor-bearing bone at 50 degrees C for 15 minutes. The patients were followed up from 4 to 180 months (mean, 63 months). The survival rate of 2, 5 and 10 years was 81.3%, 70.4%, and 53.8% respectively. The functional results were less than 50% in 4 patients, between 50% and 75% in 9, and more than 75% in 12, referred to the normal function of a normal limb. The complications consisted of infection in 4 patients, pathological fracture in 4, and separation of epiphysis in 1. Oncological results showed that local recurrences of tumor were in 4 patients, and 6 patients suffered from distant metastasis. CONCLUSION: The treatment is an alternative to replacement by prosthesis or allograft bridging techniques.