A Pediatric Case of Metastatic Conventional Parosteal Osteosarcoma Treated With Multidrug Chemotherapy.

Parosteal osteosarcoma (POS) is conventionally a low-grade sarcoma with limited metastatic potential; however, the tumor occasionally transforms into a high-grade dedifferentiated POS, which commonly metastasizes to distant organs. The present report describes a rare pediatric case of conventional POS with no dedifferentiated component yet had multiple pulmonary metastases at initial diagnosis. Following limb-sparing surgery and osteosarcoma-oriented neoadjuvant chemotherapy, the patient received total resection of pulmonary metastases. Despite no treatment for pulmonary recurrence 1 year after adjuvant chemotherapy, the patient is alive with stable disease 4 years and 6 months after the initial diagnosis.

A rare rib lesion due to parosteal osteosarcoma: a case report.

INTRODUCTION: Masses which develop on the surface of the rib bones are rare. The differential diagnosis includes benign and malignant lesions. CASE PRESENTATION: A 23-year-old European woman presented at an out-patient clinic with a 9-month history of a painless swelling on the right posterolateral side of her chest wall. The case reported here is of a very rarely seen parosteal osteosarcoma of the rib that was treated with wide resection and chest wall reconstruction. There was no evidence of local recurrence or distal metastasis after a 1-year follow-up. CONCLUSION: Parosteal osteosarcoma is a locally aggressive malignant tumor, and resection with a wide margin is the most appropriate treatment. Correct diagnosis of parosteal osteosarcoma is challenging for an orthopedic surgeon. Although rare, in the differential diagnosis of lesions located on the ribs, parosteal osteosarcoma should be considered and a systematic diagnostic approach should be taken.

Can imaging distinguish between low-grade and dedifferentiated parosteal osteosarcoma?

BACKGROUND: Most instances of the parosteal osteosarcoma (OGS) are low-grade tumors. However, some parosteal OGSs undergo dedifferentiated transformation. Dedifferentiated parosteal OGS can cause distant metastasis and poor survival, and preoperative chemotherapy may be warranted. This study provides imaging clues for dedifferentiated parosteal OGS before treatment. METHODS: The study retrospectively enrolled 23 patients with histologically proven parosteal OGS, including 69.6% (n = 16) low-grade and 30.4% (n = 7) dedifferentiated types. Preoperative images including radiography and magnetic resonance imaging were reviewed. The following imaging parameters and clinical outcomes were evaluated: 1) average age; 2) sex; 3) tumor size; 4) presence of string sign; 5) necrosis; 6) hemorrhage; 7) solid soft tissue component; 8) perforating vessels; 9) ossification grade; 10) marginal ossification; 11) periosteal reaction; 12) sunburst reaction; 13) bone marrow edema; 14) bone marrow invasion; 15) perifocal soft tissue edema; 16) adjacent joint involvement; 17) adjacent neurovascular bundle compression; 18) regional lymph node; 19) bone metastasis; 20) preoperative lung metastasis; 21) follow-up lung metastasis; and 22) recurrence. RESULTS: The average maximal tumor sizes were 7.1 cm and 10.9 cm in low-grade and dedifferentiated types, respectively (p = 0.033). Sunburst periosteal reaction was visualized in two cases of low-grade type (12.5%) and four cases of the dedifferentiated type (57.1%) (p = 0.025) of parosteal OGS. None of our studied cases revealed preoperative lung metastasis. In the follow-up chest computed tomography, lung metastasis was noted in two cases of conventional type (14.2%), and four cases of dedifferentiated type (57.1%) (p = 0.040) of parosteal OGS. In receiver operating characteristic (ROC) curve analysis, the average tumor size and sunburst periosteal reaction showed good specificity (AUC = 0.070 and 0.072, respectively). CONCLUSION: Compared with low-grade types, dedifferentiated parosteal OGS exhibits a considerably larger tumor size, more sunburst periosteal reaction, and a more frequent development of lung metastasis in the disease course. Tumor size and sunburst periosteal reaction are the most crucial imaging diagnostic factors.

Osteosarcoma presenting as supracrestal bone formation.

We report an unusual case of maxillary osteosarcoma presenting as supracrestal bone formation in a 41-year-old woman. This case is of interest from the point of view of radiographic appearance of supracrestal bone formation with widened periodontal ligaments and the buccal and palatal swelling of the tissues. Moreover, to the best of our knowledge, the histopathologic evidence of cemental resorption has not been reported earlier.

Atypical lipomas, liposarcomas, and other fat-containing sarcomas. CT analysis of fat element.

The radiographic appearance of fat in and around soft tissue sarcomas was evaluated to assess the diagnostic potential of this finding. Based on the distribution of fat and other components, these tumors are classified into three types.

Parosteal osteosarcoma of the ring finger metacarpal in a semi-professional pianist.

We report treatment of a low grade parosteal osteosarcoma of the ring finger metacarpal in a patient who would not contemplate ray amputation because of her career. Surgery involved excision of the bone, extracorporeal radiation then re-implantation.

Parosteal osteosarcoma of the skull.

Parosteal osteosarcoma of the skull is a distinct surface bone tumor, with a better prognosis than conventional osteosarcoma. The most common location is on the surface of the distal femur which accounts for 46-66% of the cases. The presentation in the skull is uncommon and there are few cases reported in the literature. We describe the case of a man who developed a parosteal osteosarcoma arising from the occipital bone with extension to the parietal bone. The patient was operated and had a complete tumor resection.

[Parosteal osteosarcoma: a clinical study of 48 cases].

OBJECTIVE: To investigate the way of diagnosis and therapy of parosteal osteosarcoma. METHODS: A retrospective review was conducted of 48 patients treated at our department between June 1964 and December 2001. The average age of patients in this study was 29.2 years (13 - 47 years). Thirty-two of the patients were female; sixteen were male. The single most common site is the posterior aspect of the distal femur (in 36 patients), followed by the femur shaft (in 6 patients), the proximal tibia (in 2 patients), etc. Nine patients had been operated on before referral to our department. RESULTS: The average follow-up period from the first operation was 5.2 (0.25 - 24) years. In 36 of the 39 patients in whom a limb-salvage procedure was performed, a segment of the tumor-bearing bone was excised along with the tumor, whereas in 3 patients only the subadjacent cortex was excised with the tumor. In the limb-sparing group, the reconstruction was achieved by means of attenuated tumor bone or allograft in 23 cases, by endoprosthetic replacement in 9 cases, and by allograft replacement in 4 cases. The local resections were wide in 35 cases, and marginal in 13 cases. After marginal surgery, local recurrence occurred in 5/13 patients, whereas it occurred in 3/35 patients treated with wide resection. Pulmonary metastases developed in 6 patients, four patients died, and 2 patients are alive with disease. There were 4 cases of fractures of bone grafts. Four patients developed an infection. Long-term survival rate is 85.8%. For tumors that invaded the medullary canal there was no statistical association with local recurrence or metastasis. There is statistical significance between surgical margin and local recurrence. CONCLUSIONS: Wide surgical excision alone is adequate treatment for patients with conventional parosteal osteosarcoma. A tumor-free margin remains the critical factor determining overall prognosis. When a marginal excision was knowingly done to preserve a major neurovascular bundle, the risk of recurrence was less than when it was done to shell-out a presumptively benign lesion. Repeated recurrence probably increases the risk of dedifferentiation and thereby worsens the prognosis. Recurrent lesions with multiple soft-tissue satellite nodules or involvement of the neurovascular structures may however require amputation to provide sufficient local control when a wide margin cannot be achieved. An individualized resection will be performed in the future probably under the help of the advanced technique of image to distinguish the reactive zone from the normal tissue precisely.

Parosteal osteosarcoma.

A case of parosteal osteosarcoma is reported. In spite of the pathognomonic plain radiographic signs of parosteal osteosarcoma, it is very uneasy to differentiate it from myositis ossificans circumscripta in the mature stage. CT and MRI defined the extent of the tumor into the soft tissue, the medullary and cortical invasion and gave more information about the composition of the lesion.

Peripheral ossifying fibroma and juxtacortical chondrosarcoma in cynomolgus monkeys (Macaca fascicularis).

Literature on spontaneous primary bone tumors in nonhuman primates is sparse. This case report describes 2 different neoplastic bone lesions in 2 adult cynomolgus monkeys (Macaca fascicularis), including macroscopic, radiographic, histologic, and immunohistochemical findings. In one monkey, a firm mass located at the palatogingival junction of the left rostral maxilla was confirmed to be a peripheral ossifying fibroma in light of its histologic and immunohistochemical characteristics. In another monkey, a lobulated tumor at the right distal femur that radiographically showed moderate radiopacity with splotchy areas of mineralization was confirmed to be a juxtacortical chondrosarcoma on histologic examination. The 2 neoplastic bone lesions revealed rare histologic and immunohistochemical characteristics and contribute to the known tumor spectrum of cynomolgus monkeys.

Parosteal osteosarcoma of the orbit.

A 60-year-old woman was referred to Bristol Eye Hospital because of a progressive, painless, right proptosis. CT revealed a well-defined, hyperdense lesion adjacent to the lateral orbital wall. A marginal excision was performed. The mass was stony-hard, lobulated, and encapsulated. Histopathologic findings were consistent with a low-grade parosteal osteosarcoma. Parosteal osteosarcoma is a rare osteogenic tumor that usually affects the long bones. It represents a malignant, though well differentiated, tumor that has a relatively good prognosis after a wide excision. However, local recurrences are not rare and have been associated with dedifferentiation. The latter affects the prognosis adversely and, thus, regular follow-ups are strongly suggested after the initial tumor excision. In the present case, no further treatment was administered and the patient was reported disease free 26 months after surgery.

MRI findings in parosteal osteosarcoma: correlation with histopathology.

PURPOSE: To assess the role of magnetic resonance imaging (MRI), particularly signal intensity changes, in predicting the dedifferentiation of parosteal osteosarcoma, and to evaluate other factors that may affect grading on MRI. MATERIALS AND METHODS: MRI of 12 patients with parosteal osteosarcoma diagnosed on plain radiography were reviewed with regard to size, location, extent, soft tissue component, intramedullary invasion, and signal characteristics. The findings are correlated with histopathologic results. RESULTS: By histopathological examination there were 6 Grade I, 3 Grade II, and 3 Grade III tumors. Average size was 11 cm. All cases had a soft tissue component. Intramedullary extension was evident in 3/6 of the Grade I cases, 2/3 of the Grade II cases, and all (3/3) of the Grade III cases. T1-weighted images revealed lesions of marked hypointensity. Signal intensity on T2-weighted images varied with the presence of necrosis and hemorrhage in relation to size, regardless of the grade of the tumor. Contrast-enhanced images revealed enhancement of the solid components; no enhancement was observed in the necrotic or hemorrhagic parts. CONCLUSION: High and heterogeneous signal on T2-weighted images of Grade I, II, and III tumors is not specific for the dedifferentiated component, due to hemorrhage and necrosis in large masses. Therefore, high signal intensity on T2-weighted images is not always a reliable way to predict the grade of the tumor. Contrast enhanced T1-weighted images can be valuable to show the solid component in the heterogeneous areas on T2-weighted images, and can be useful in guiding the biopsy.

Radiological appearances of appendicular osteosarcoma: a comprehensive pictorial review.

Osteosarcoma is the most common primary malignant tumour of bone in adolescents and young adults. Hence, a comprehensive knowledge of the common and unusual imaging appearance of this tumour is essential. Correct diagnosis of the various varieties of osteosarcoma is important for optimal clinical management including staging, biopsy, treatment and follow-up of patients. This review article provides a comprehensive approach to the radiological diagnosis of the different types of appendicular osteosarcoma and illustrates the role of CT and MRI in further characterisation.

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.

Case report 835: Parosteal osteosarcoma involving the left radius.

A case of parosteal osteosarcoma arising in the radius was presented. The site is uncommon, being represented in about 1% of all reported cases of parosteal osteosarcoma. The clinical and radiographic characteristics of this lesion were described and the histological as well as the differential diagnosis discussed.

Dedifferentiated parosteal osteosarcoma of the radius.

A 35-year-old woman presented with a painful swelling in the left distal radius that had been present for 1 year. Radiography and computerized tomography revealed a sclerotic surface lesion that had grown over the year and eroded the cortex. Histological examination demonstrated two distinct components: a cartilaginous low- to moderate-grade osteosarcoma on the surface and a high-grade osteosarcoma in the intramedullary component. This case is uncommon in two aspects: the radius is a rare site for such a tumor and the dedifferentiation was revealed at the time of the first surgery and was not secondary to recurrence.

Radiological features of osteogenic sarcoma of the jaws. A comparative study of different radiographic modalities.

OBJECTIVE: To evaluate the clinical and radiological features of osteogenic sarcoma of the jaws with particular reference to the effectiveness of the radiographic modalities used. MATERIAL AND METHODS: A total of 66 cases (57 from the English-language literature and nine new cases) were critically evaluated for the features depicted with intra-oral and panoramic radiography and CT. RESULTS: The mean age of the patients was 36 years (median 31.5 years). There were no differences in gender distribution. A ratio of 1:1.6 between the maxilla and the mandible was found. Lesions had diffuse borders in 78% of cases and defined but not corticated borders in 22%. Twenty-nine per cent were radiolucent, 29% radiopaque and 41% mixed density. Widening of the periodontal ligament space (PDL) was seen in 14 of the 47 (28%) lesions associated with teeth and structural changes in the mandibular canal in 34% of the mandibular lesions. There was a periosteal reaction in 48% and soft tissue involvement in 33% of the lesions. CONCLUSIONS: Widening of the PDL space was best demonstrated on periapical radiographs. Structural changes in the mandibular canal were shown mainly with panoramic radiographs. Periosteal reaction was best demonstrated by occlusal radiographs and soft tissue involvement by CT. Thorough radiological examination using periapical, occlusal and panoramic radiography, and recognition of the radiological features of osteogenic sarcoma should lead to earlier diagnosis.