Parosteal osteogenic sarcoma arising in cranial bones: clinical and radiologic features in eight patients

A review of imaging of surface sarcomas of bone

Surface lesions of bone are uncommon. Although their imaging features generally mirror those of their intramedullary counterparts, surface lesions may demonstrate distinct characteristics which along with their unusual location present a diagnostic challenge. Surface sarcomas are usually of a lower grade compared with intramedullary variants, leading to differences in management. Osteosarcoma arising from the cortical surface of the bone is termed juxtacortical or surface osteosarcoma and includes three distinct entities: parosteal, periosteal, and high-grade surface osteosarcoma. We also review the features intracortical osteosarcoma, which some authors include under the umbrella term surface osteosarcoma. These lesions exhibit biologic features distinct from those of conventional intramedullary osteosarcoma, which underlines the importance of accurate imaging diagnosis. Periosteal chondrosarcoma and periosteal Ewing sarcoma also have distinctive imaging appearances. The purpose of this article is to review surface sarcomas of bone with regard to their clinical and radiological features and to discuss the differential diagnosis for each condition.

Dedifferentiated parosteal osteosarcoma of the calvaria

Dedifferentiated parosteal osteosarcoma is a rare tumor and is even rarer when involving the skull bones. We present a case of a 57-year-old man with a partially ossified progressive enlarging left skull mass in the left temporoparietal region, with erosion of the outer table. Radiological diagnosis of dedifferentiated parosteal osteosarcoma was suggested, and histopathology confirmed the diagnosis.

Parosteal Osteosarcoma of the Distal Radius Mimicking an Osteochondroma-A Diagnostic Misadventure

We present a case of a parosteal osteosarcoma mimicking an osteochondroma with atypical clinical features, radiographic findings, and histological examination. This report serves to exemplify the importance of recognizing the similarities between these 2 entities and other peculiar features that will help to differentiate between sessile osteochondromas and parosteal osteosarcomas, to prevent misdiagnosis.

Distinctive Head and Neck Bone and Soft Tissue Neoplasms

Benign and malignant primary bone and soft tissue lesions of the head and neck are rare. The uncommon nature of these tumors, combined with the complex anatomy of the head and neck, pose diagnostic challenges to pathologists. This article describes the pertinent clinical, radiographic, and pathologic features of selected bone and soft tissue tumors involving the head and neck region, including angiofibroma, glomangiopericytoma, rhabdomyosarcoma, biphenotypic sinonasal sarcoma, chordoma, chondrosarcoma, and osteosarcoma. Emphasis is placed on key diagnostic pitfalls, differential diagnosis, and the importance of correlating clinical and radiographic information, particularly for tumors involving bone.

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.

Parosteal Osteosarcoma

Parosteal osteosarcoma is a rare malignant bone tumor arising from the bone cortical surface. It most commonly occurs in young women over the metaphyseal region, especially the long bones near the knee joint. Patients usually report a slow-growing mass for years. The tumor is characterized by its bland microscopic morphology, prone to be misdiagnosed as other benign tumors. In the absence of dedifferentiation, the prognosis is generally better than that of conventional osteosarcoma. Recent studies demonstrated distinctive cytogenetic abnormality resulting in amplification of the CDK4 and MDM2 genes, which may serve as markers for molecular diagnosis. In this article, we review the clinical, radiologic, and pathologic features of parosteal osteosarcoma and identify some diagnostic pitfalls, discuss the prognostic variables, and update recent molecular advances and their application in the diagnosis.

Bone Lesions of the Head and Neck

This article describes the clinical, radiographic, and pathologic features of tumors and tumorlike lesions affecting the bones of the head and neck region. Emphasis is placed on common bone lesions affecting the craniofacial skeleton, particularly those that occur with more frequency or those that are unique to this part of the skeleton. Several of these lesions pose a diagnostic challenge to the pathologist. To ensure that a correct diagnosis is rendered, it is of utmost importance that accurate and detailed clinical and radiographic information is available.

De novo osteogenic sarcoma of mastoid bone

The most common primary malignant tumor of the bone is osteosarcoma. Primary involvement of the craniofacial bones in osteosarcoma is relatively rare. The mandible and the maxillae are the most commonly affected bones of the head. Here, we report a rare case of de novo high-grade osteogenic sarcoma of the mastoid region of the temporal bone and discuss the diagnostic and therapeutic properties.

Protuberant fibro-osseous lesion of the temporal bone: "Bullough lesion"

Primary tumors of the calvarium are infrequent, and with the exception of osteoma, lesions confined to the surface of the skull are very rare. The differential diagnosis includes benign and malignant matrix forming tumors, other mesenchymal tumors, and reactive lesions. Fibro-osseous lesions are characteristically centered within bone and surface fibro-osseous lesions always prompt consideration of parosteal osteosarcoma, which is rare but well documented in the calvarium. We present 2 cases of a distinctive lesion of the temporal bone intimately related to the occipito-mastoid suture and typically presenting as a retroauricular soft tissue mass with calcific densities, confined to the soft tissues on the outer table of the skull without intraosseous involvement. The lesion is characterized histologically by rounded and ovoid zones of ossification within a bland fibrous stroma. The first 2 cases were documented in 1999 as "Protuberant fibroosseous lesion of the temporal bone.:" We present a further 2 cases, 1 of 2 years duration and the other with a 10-year history. This distinctive entity, which must be distinguished from other fibro-osseous lesions, including subtle low-grade parosteal osteosarcoma, seems to behave in a benign fashion and thus far recurrence is not documented. Local excision seems adequate. The pathologic features in the original report were documented by Prof Peter Bullough. As these cases were recognized by him alone we propose calling this entity "Bullough lesion" or, better still, "Bullough's Bump!"

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.

Two unusual osteogenic orbital tumors: presumed parosteal osteosarcomas of the orbit

OBJECTIVE

To report two cases of suspected parosteal osteosarcoma of the orbit, with dedifferentiation into a high-grade liposarcoma occurring in one patient.

DESIGN

Two retrospective case reports.

METHODS

The clinical, radiologic, and pathologic records of two patients with suspected orbital parosteal osteosarcoma were retrospectively reviewed.

MAIN OUTCOME MEASURES

Histologic evaluation and clinical follow-up were measured.

RESULTS

The first patient was a 47-year-old male presenting with a 5-month history of painless right lower lid swelling; excision biopsy suggested a well-differentiated parosteal osteosarcoma of the orbital floor, which recurred 3 years later. Six months after excision of the recurrence, the mass demonstrated accelerated growth, and a lid-sparing exenteration was performed; histologic examination showed a high-grade liposarcoma. The patient remains disease-free at 4 years. The second patient, a 40-year-old male, presented with an 8-year history of proptosis and a right superotemporal orbital mass. The mass was excised completely at lateral orbitotomy; histologic examination suggested a well-differentiated parosteal osteosarcoma. The patient remains well 9 months postoperatively.

CONCLUSIONS

Parosteal osteosarcoma is an uncommon tumor, usually affecting long bones, that is extremely rare in the orbit. It is a low-grade sarcoma that tends to recur locally after excision but has a favorable prognosis. Dedifferentiation into a high-grade sarcoma occasionally occurs in parosteal osteosarcoma, but transformation into liposarcoma does not seem to have been previously reported. It is important to recognize dedifferentiated parosteal osteosarcoma, because the prognosis is poor, and radical treatment may be required.

Periosteal osteosarcoma of the jaws: report of 2 cases

Osteosarcoma (OS) occurs most often in the long bones. OS of the jaws has clinical and biologic aspects different from those of the long bones. They tend to occur at an older mean age, pain and swelling are more typical, and prognosis is more favorable. Nearly all OS shows a very prominent central intramedullary bone component. Only rarely are juxtacortical (peripheral) OS located in the jaws. There are 2 main types of juxtacortical OS, periosteal and parosteal. We present 2 cases of OS of the jaws where the clinical, radiologic, and histologic findings pointed to a diagnosis of periosteal OS. Both patients presented, in fact, with lesions located superficially on the bone surface with no marrow involvement. Both tumors were characterized by the presence of a moderately differentiated chondroblastic tumor with foci of osteoid and bone formation. Periosteal OS should be differentiated microscopically from periosteal chondrosarcoma, intramedullary OS with periosteal extension, high-grade surface OS, and parosteal OS. The clinical differential diagnosis was done, in these cases, for epulis, gingival tumors, peripheral odontogenic fibroma, peripheral ossifying fibroma, pyogenic granuloma, peripheral giant cell granuloma, and mesenchymal malignant tumors.

Parosteal osteogenic sarcoma of the mastoid bone

Parosteal osteogenic sarcoma (POS) is an uncommon surface bone tumor, most often arising from the metaphyseal end of long bones. Involvement of the cranial bones is rare, with only 1 case of mastoid bone POS previously reported in the literature. Two patients with POS of the mastoid are presented, 1 followed up for 25 years after surgical treatment. The presenting signs and symptoms, as well as distinctive radiographic findings, are discussed. Histologic features are also described. Typically, cranial POS appears as a sessile, densely ossified surface growth with radiating bone spicules that blend with surrounding soft tissue. Treatment is en bloc resection, which is curative in most cases.

Parosteal osteosarcoma of the maxilla

We describe the case of a 47-year-old female who presented with a small nodule in the buccal sulcus in the left maxillary incisor region. Clinical and radiographic examination revealed a small sclerotic neoplasm with a short pedicle. Histopathological examination confirmed a diagnosis of parosteal osteosarcoma. The contribution of CT to the diagnosis and management is discussed.

Parosteal osteosarcoma. A clinicopathological study

The records of 226 patients (sixty-seven who were managed at our institution and 159 who were identified from the consultation files) who had had a parosteal osteosarcoma were reviewed. The criteria for diagnosis were that, roentgenographically, the lesion had arisen from the surface of the bone and that, histologically, the tumor was well differentiated (Grade 1 or 2); it was characterized by well formed osteoid within a spindle-cell stroma; and, when there was medullary involvement, less than 25 per cent of the medullary cavity was affected. Dedifferentiation was more common (16 per cent of the patients) than previously reported and was associated with a poor prognosis. Cross-sectional imaging studies demonstrated medullary involvement in 22 per cent of the patients, an unmineralized soft-tissue mass peripheral to the mineral component in 51 per cent, and adjacent soft-tissue invasion in 46 per cent. In contrast to the findings in our previous studies, medullary involvement was not a poor prognostic factor. At an average of thirteen years (range, two to forty-one years), eleven of the sixty-seven patients who were managed at our institution died of the tumor; ten of these patients had a dedifferentiated tumor. Statistical analysis of the thirty-nine patients who had had the primary treatment at our institution revealed that incomplete resection was associated with an increased risk of local recurrence and that dedifferentiation markedly increased the risk of metastasis.

Primary osteosarcoma of the skull--a case report and review of the literature

Primary osteosarcoma of the skull (POS) in a young man with intracranial involvement is reported. After an initial transient remission by surgical intervention and chemotherapy, he began to deteriorate due to tumor recurrence and intracranial hemorrhage, and died 15 months following the time of diagnosis. The rarity and poor prognosis of POS are emphasized together with the review of the clinical and therapeutic aspects in the previously reported 98 cases in the literature.