It most commonly occurs in young women over the metaphyseal. Unlike conventional osteosarcomas, it involves an older age group typically in the 3 rd and 4 th decades of life and shows a slight female. Surface tumours of bone may be a cause of confusion and diagnostic difficulty. Here, we report a first case of dedifferentiated parosteal osteosarcoma of the head and neck.
The grade g of the tumor, which is a measure of how likely it is to grow and spread, based on how it looks under the microscope. Confusion may arise from the several descriptive adjectives used parosteal, periosteal and juxtacortical. Trabeculae appear also as parallel streamers with broken cement lines as pagetic mosaic. We report two cases mimicking an osteochondroma, radiologically and histologically and propose an explanation. Webpathology is a free educational resource with 10328 high quality pathology images of benign and malignant neoplasms and related entities. Heavily ossified, hard, tanwhite, somewhat lobulated mass attached to the underlying cortical bone. Parosteal osteosarcoma of the orbit is a rare entity, with only 3 presumed cases having been reported in the literature to date. Parosteal osteogenic sarcoma of the hand walt 1990 histopathology wiley online library skip to article content. Osteosarcoma is the most common malignant bone tumor. Dedifferentiated parosteal osteosarcoma of the maxilla. Parosteal os is composed by spindle cells and collagen fibers embedding osseous trabeculae. Parosteal osteosarcomas are rare, lowgrade juxtacortical variant of osteosarcoma, especially in the jaws, representing 1. Osteosarcoma osteogenic sarcoma is a malignant tumor whose neoplastic cells present osteoblastic differentiation and form tumor bone. However, fibrous or cartilaginous tissue may coexist or even predominate.
Parosteal osteosarcoma of the skull, histopathology 10. Departments of histopathology, enfield district hospital, enfield, middlesex and morbid anatomy, the london hospital, london, uk. It is treated like conventional osteosarcoma figures 5,6. A system commonly used to stage osteosarcoma is the msts system, also known as the enneking system. It typically presents in early adulthood and middle age with a. Mar 16, 2020 webpathology is a free educational resource with 10328 high quality pathology images of benign and malignant neoplasms and related entities. Note intact cortex otthe radius and thepoorly ossified periphery ofthe tumor, representing areas ofpredominant vol bc, no. Parosteal osteosarcoma is a subtype of osteosarcoma and arises from the outer layer of the periosteum.
By histopathological examination there were 6 grade. Parostealt osteosarcoma is situated on the bone surface usually distally on the femur and show a low grade fibroblastic growth pattern with bone production. Histopathology and molecular pathology of bone and extraskeletal osteosarcomas. We report a case of parosteal osteosarcoma arising in the metacarpal. Giant cell rich parosteal osteosarcoma, histopathology. It has not been described to arise from sites other than the major tubular bones. Its relatively benign course was described by muller as early as 1843, but it was not before 1947 that parosteal.
Parosteal osteosarcoma is a rare malignant bone tumor arising from the bone cortical surface. These cells produce osteoid describing irregular trabeculae amorphous, eosinophilicpink with. Parosteal osteosarcoma is a lowgrade, malignant, boneforming tumor that arises on the surface of bone. It accounts for about 4% of all osteosarcomas and, although rare, it is the most common type of osteosarcoma of the bone surface. Of the 147 conventional parosteal osteosarcoma, 119 87. Giant cell rich parosteal osteosarcoma, histopathology 10. Parosteal osteosarcoma occurs in the periosseous tissues. Several incidences of dedifferentiation in cpos were reported by earlier studies 1824% 1,2,3. Diagnostic difficulties may arise from the lack of awareness of less common entities, insufficient biopsy sampling and a failure to understand the precise relationship of a lesion and the bone surface. Gnas mutations are not detected in parosteal and lowgrade. It is the most common type of juxtacortical or surface osteosarcoma and accounts for 5% of all osteosarcomas.
Parosteal osteosarcoma radiology reference article. Parosteal osteosarcoma is a lowgrade, malignant bone tumor that usually arises on the metaphyseal surface of long bones. Parosteal osteosarcoma is a low grade, well differentiated fibroblastic tumor that produces boneosteoid immature woven bone. It typically presents in early adulthood and middle age with a peak incidence in the third decade. Jun 28, 2014 parosteal osteosarcomas are rare, lowgrade juxtacortical variant of osteosarcoma, especially in the jaws, representing 1. Unlike conventional osteosarcomas, it involves an older age group typically in the 3 rd and 4 th decades of life and shows a slight female predilection 1, 3, 4. Departments of ophthalmology and histopathology, aristotle university of thessaloniki, thessaloniki, greece. Osteo boneosteoid tissue sarcoma malignant tumour of connective tissue 020412 dr. Dedifferentiated parosteal osteosarcoma dpos is defined as a highgrade surface osteosarcoma which rarely occurs as either a primary or secondary event of conventional lowgrade parosteal osteosarcoma cpos. Histopathology and molecular pathology of bone and extraskeletal osteosarcomas helen trihia and christos valavanis metaxa cancer hospital, department of pathology and molecular pathology unit greece 1. Parosteal osteosarcoma is a welldifferentiated variant of osteosarcoma that affects the surface of the bone. Periosteal osteosarcoma, as described in chapter 11, is distinctly different from parosteal osteosarcoma radiographically and histologically. Dedifferentiated parosteal osteosarcomas, which are high grade lesions, can occur in a wide age distribution. Cells form long sweeping fascicles with parallel nuclei.
The tumor is usually located at the posterior aspect of the distal femur in about 70% of cases, followed by the. Parosteal osteosarcoma pos is a slowgrowing tumor which originates from the outer layer of the periosteum and represents 65% of surface osteosarcomas and in our database accounts approximately for 4, 8% of all osteosarcomas. Parosteal osteosarcoma is a lowgrade malignant tumor which is capable of dedifferentiation. Histopathology and molecular pathology of bone and. Presentations ppt, key, pdf logging in or signing up. About 50% of these tumors demonstrate chondroid differentiation. Parosteal osteosarcoma, secondary chondrosarcoma are also confusing at times in histopathology findings. Fewer than 50 cases of osteosarcoma involving the hand have been reported in the literature. The findings are correlated with histopathologic results. It arises from the surface of the bone, namely the outer layer of the periosteum.
A parosteal osteosarcoma of the distal femur with a typical radiographic and macroscopic appearance is reported. Parosteal osteosarcoma definition of parosteal osteosarcoma. M alignant bone tumors are rarely seen in the hand. Diagnostic and treatment problems with parosteal osteosarcoma. Diagnostic evaluation and biopsy techniques for primary bone tumors, an overview of treatment and outcomes, principles guiding surgical management of bone sarcomas, and chemotherapy in the. Parosteal osteoid sarcoma, sometimes referred to asjuxtacortical osteogenic sarcoma, is a rare malignant bone tumor which must be differentiated from an osteosarcoma clinically, roentgenologically, and histologically. Most common type of juxtacorticalsurface osteosarcoma.
Nov 14, 2019 parosteal osteosarcoma occurs in the periosseous tissues. Convention foc fibroblastic, osteogenic, chondroblastic. Pdf to assess the role of magnetic resonance imaging mri, particularly signal. You may not embed one of our images on your web page without a link back to our site. Tumor cells are very pleomorphic anaplastic, some are giant and present numerous and atypical mitotic figures. Mri findings in parosteal osteosarcoma diagnostic and. In single cases the underlying cortex and bone marrow might be infiltrated. If you would like a large, unwatermarked image for your web page or. The vast majority involve the metaphysis of the femur, humerus, or tibia. They are directed toward diaphysis and may have medullary canal is in continuity with that of the. Ahuja and coauthors and, more recently, ritschl and coauthors have tended to consider all surface osteosarcomas to be parosteal and have distinguished them by the histologic grade.
References 1 article features images from this case. Intracortical osteosarcoma is very rare highgrade osteosarcoma that from histological point of view is osteoid or maybe bone formation. Osteosarcoma is thought to arise from primitive mesenchymal boneforming cells, and its histologic hallmark is the production of malignant osteoid. On histology the tumour was dominated by large numbers of osteoclast. Aug 17, 2018 parosteal osteosarcomas are usually lowgrade tumors, however, sometimes they transform to highgrade tumors, which is named dedifferentiation. It is a highgrade sarcoma, very aggressive, without escape in terms of surviving. The most commonly affected sites, in descending order, are the distal femur typically the posterior surface, the proximal humerus, the proximal femur, the proximal tibia, and the proximal ulna. Gnathic osteosarcoma jaw bones usually chondroblastic. The most common type of osteosarcoma is the primary, high grade, intramedullary conventional osteosarcoma, which represents approximately 75% of all osteosarcomas definitions. Features are consistent of parosteal osteosarcoma which is low grade tumor arising from the outer periosteal layer. Osteosarcoma os is a malignant spindle cell sarcoma in which the malignant cells produce osteoid or bone in the background of a sarcomatous stroma. Only 12 cases of intraoral parosteal osteosarcomas have been reported in the english literature.
Recently, we encountered a patient with dedifferentiated parosteal osteosarcoma occurring in the maxilla. Introduction osteosarcoma has been recognized for almost two centuries and is the most common. It has a slight female predominance and most frequently occurs in the third decade of life, 2 which is a decade older than the peak age of the conventional counterpart. Bizarre parosteal osteochondromatous proliferation arises. Approximately 8% to 25% of the cases reported in literature developed dedifferentiation, which was reported to had increase. There was no spatial relationship between the giant cells and areas of. Conventional osteosarcoma with periosteal spread high grade surface osteosarcomas. Most of the neoplastic bone lacked osteoblastic rimming. Medullary extension of parosteal osteosarcoma has been seen in 22% to 58% of patients, and this finding itself is not considered significant in the prognosis. I parosteal osteosarcoma i43 cartilaginous and fibrous tissue. Only 12 cases of intraoral parosteal osteosarcomas have been reported in. The classic or socalled conventional osteosarcoma develops in the medullary cavity of the metaphysis of long bones. Other cell populations may also be present, as these types of cells may.
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