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. A 32yearold man presenting to the head and neck surgical oncology clinic with a 1year history of a firm palatal mass. The parosteal os component in dedifferentiated parosteal os would not be overlooked if careful radiographic imaging studies were performed. Parosteal osteosarcoma proximal humerus age 28 hi my name is cheryl. A radiohistologic approach on two cases zafiria g papathanassiou1, marco alberghini2, philippe thiesse3, marco gambarotti2, giuseppe bianchi4, cristina tranfaglia5 and daniel vanel1 abstract objective. The first reported patient underwent a resection of the affected rib, one rib above and below the tumor, and the surrounding soft tissue and parietal pleura. Cortex continuity and in a lesser degree merge of medullary cavities, which are by definition expected in osteochondromas, may be atypically seen in pos. Osteosarcoma is the name given to a heterogeneous group of malignant spindle cell tumors that have as their common feature the production of immature bone, also known as osteoid.
Nov 14, 2019 parosteal osteosarcoma usually occurs in older age with a peak in the third and fourth decades of life, with no sex predilection. Parosteal osteosarcoma with pulmonary metastases in a cat. The tumor is characterized by its bland microscopic morphology. Parosteal osteosarcoma of the fibula in a middleaged patient ncbi.
We examined 24 primary osa tumor specimens six parosteal, 16 intramedullary and two extraskeletal and four unrelated metastases. The importance of making the diagnosis of periosteal osteosarcoma cannot be understated owing to the distinct natural history and that resection alone is a standard treatment for parosteal osteosarcoma, while resection and adjuvant chemotherapy are standard treatments for highgrade surface osteosarcoma. Specifically, it is an aggressive malignant neoplasm that arises from primitive transformed cells of mesenchymal origin and thus a sarcoma and that exhibits osteoblastic differentiation and produces malignant osteoid. Its relatively benign course was described by muller as early as 1843, but it was not before 1947 that parosteal. Also called juxtacortical osteosarcoma outside of the periosteum ages 30 60 years, either no gender preference or female predominant. To evaluate the most significant features of parosteal osteosarcoma and to describe the most frequent findings on conventional radiology. Parosteal osteosarcoma is a lowgrade welldifferentiated malignant tumor. Parosteal osteosarcoma is slowgrowing and late to metastasize.
Parosteal osteosarcoma is a welldifferentiated variant of osteosarcoma that affects the. Osteosarcoma os is a malignant spindle cell sarcoma in which the malignant cells produce osteoid or bone in the background of a sarcomatous stroma. Four years after the biopsy, the patient was asymptomatic. The patient developed lung metastasis and a mass in the interosseus membrane of the forearm proximally to the osteotomy. Pdf a popliteal giant synovial osteochondroma mimicking. Osteo boneosteoid tissue sarcoma malignant tumour of connective tissue 020412 dr. Parosteal osteosarcoma is a lowgrade tumor that grows predominantly on the surface of long bones, in an exophytic pattern.
Owing to the parosteal location, bpop must be distinguished from parosteal osteosarcoma, which is rarely found in the hands and feet. Jul 25, 2011 parosteal osteosarcoma is a welldifferentiated variant of osteosarcoma that affects the surface of the bone. Periosteal osteosarcoma that is low grade to intermediate grade. The lesion might be mistaken for osteochondroma because of its surface location and cartilaginous component 3. Incisional biopsy demonstrated parosteal osteosarcoma with woven bone in a fibrous stroma, including nuclear atypia characteristic of a lowgrade osteosarcoma figure 3. Coamplification and overexpression of cdk4, sas and mdm2. The information provided on this site is designed to support, not replace, the relationship that exists between a patientsite visitor and hisher existing physician. The incidence is highest in the third and fourth decades of life 810 most frequently affecting women 7,912. Because it is derived from the outer layer of the periosteum, it grows without causing elevation of the periosteum or evidence of periosteal new bone formation. A radiohistologic approach on two cases article pdf available july 2011 with 323 reads how we measure reads. A preexisting bone lesion suggestive of pagets disease of bone. Patients usually report a slowgrowing mass for years.
Gnas mutations are not detected in parosteal and lowgrade. This is the second case of parosteal osteosarcoma of the tarsus reported in the english literature. Parosteal osteosarcomas account for 3% of all osteosarcomas. Learn more about parosteal osteosarcoma from related diseases, pathways, genes and ptms with the novus bioinformatics tool. Parosteal osteosarcomas are rare, lowgrade juxtacortical variant of osteosarcoma, especially in the jaws, representing 1. As a result, nearly all patients with osteosarcoma with the exception of patients with lowgrade parosteal osteosarcomas and some patients with periosteal and craniofacial osteosarcomas, where the value of chemotherapy is not as clear are treated with adjuvant chemotherapy, and most receive some neoadjuvant chemotherapy in the preoperative. Due to the nonaggressive and noninvasive nature of parosteal osteosarcoma, it must be distinguished from other benign lesion and several differential diagnoses can be considered. Multimodal treatment of highgrade localised osteosarcoma increases dfs from only 1020% to 60% when compared to surgery alone. It is the most common primary cancer of bone in children and adolescents. Tumor biology and incidence rare, lowgrade lesion arising on surface of cortex classified as highgrade surface osteosarcoma if highgrade cytological changes observed this lesion may contain fibrous, osseous or cartilaginous elements most common osteosa. Parosteal osteosarcoma of the skull is a distinct surface bone tumor, with a better prognosis than conventional osteosarcoma. Periosteal osteosarcoma is an intermediategrade chondroblastic.
Epidemiology it is the second most common type of juxtacortical or surface osteosarcoma after parosteal osteosarcoma and accounts for 1. Only 12 cases of intraoral parosteal osteosarcomas have been reported in the english literature. Also known as osteogenic sarcoma explanation of parosteal osteosarcoma. What are the risk factors for parosteal osteosarcoma. Surface parosteal osteosarcoma parosteal osteosarcoma paos is a lowgrade. A poorly defined softtissue component distinct from the ossific matrix is the most distinctive feature of highgrade parosteal osteosarcoma. All six cases were initially misdiagnosed as benign lesions on pathologic evaluation. The peripheral osteosarcomas are represented by parosteal, periosteal and high grade surface osteosarcomas. It is usually considered as an osteosarcoma variant, which must. A staging system is a standard way for the cancer care team to sum up the extent of the cancer. It has not been described to arise from sites other than the major tubular bones.
Paraosteal osteochondromatosis proliferation noras. Parosteal osteosarcoma is a subtype of osteosarcoma and arises from the outer layer of the periosteum. While there is a risk of transformation to conventional os if treated with curettage alone, the prognosis is signi. We showed the tumor arose at the periphery of the bone by ct and mri. The fibrous and cartilaginous elements of each tumour were graded from i to iv for malignancy. The lung mass was found to be a metastasis from parosteal osteosarcoma and the biopsy of the forearm mass revealed a myositis ossificans. 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. The majority of osteosarcoma cases of the head and neck are highgrade lesions. Radiographs and ct demonstrate a parosteal osteosarcoma of the distal femur these images are from dr. This is the third reported case of a rib parosteal osteosarcoma. Parosteal definition of parosteal by medical dictionary.
Osteosarcoma is a cancer of the bone that destroys tissue and weakens the. Parosteal osteosarcoma is a rare malignant bone tumor arising from the bone cortical surface. It arises from the surface of the bone, namely the outer layer of the periosteum. All 17 highgrade lesions evaluated with mr imaging were of predominantly high signal intensity on t2weighted images.
Abstract parosteal osteosarcoma is a rare malignancy of the bone that usually. This neoplasm also has been called juxtacortical os teogenic sarcoma, parosteal osteogenic sarcoma, ossifying par osteal sarcoma, juxtacortical osteosarcoma, and parosteal os. A midthigh amputation was performed and the diagnosis substantiated by final histologic study. We present a case and discuss the diagnostic and therapeutic implications of a rare lowgrade parosteal osteosarcoma. Probable periosteal osteosarcoma in a rabbit esther van praag the word sarcoma comes from the greek and means fleshy excrescence. The peripheral osteosarcomas are represented by parosteal, periosteal and highgrade surface osteosarcomas. It describes a group of malignant tumors in which a primitive mesenchymal cell can evolve in several directions and, thus, into different types of sarcomas. The classic or socalled conventional osteosarcoma develops in the medullary cavity of the metaphysis of long bones. Parosteal osteosarcoma, or juxtacortical osteosarcoma, is a rare form of osteosarcoma that develops at the bone surface, but has a better prognosis than other conventional osteosarcomas.
It accounts for about 4% of all osteosarcomas and, although rare, it is the most common type of osteosarcoma of the bone surface. If areas of lucency are not seen on radiography, and histological examination does not reveal spindle cell proliferation, a diagnosis of osteoma can be considered. Also called juxtacortical osteosarcoma outside of the periosteum ages 30 60 years, either no gender preference or female predominant arises in metaphyses of long bones. Parosteal osteosarcoma from a rib the annals of thoracic. Open biopsy is required to rule out a malignant bone tumour, even if parosteal osteoma is suspected based on the clinical course and imaging findings. In some occasions, it may progress to high grade and become fatal. Parosteal osteosarcoma of the mandible on ct and mri findings. Pdf parosteal osteosarcoma is a welldifferentiated variant of osteosarcoma that affects the surface of the.
Parosteal osteosarcoma of the humerus j request pdf. Pdf parosteal osteosarcomas are rare, lowgrade juxtacortical variant of osteosarcoma, especially in the jaws, representing 1. Parosteal osteosarcoma, uncommon or relatively unrecog nized in veterinary medicine. The most challenging differentiation is from osteochondroma because both tumors share some common clinical and morphologic features. On the other hand, it is not unusual for parosteal osteosarcoma to be treated with definitive operative resection without a previous biopsy.
You will find some basic information about this disease and the parts of the body it may affect. Good prognosis better than high grade osteosarcoma, poorer than parosteal osteosarcoma or juxtacortical chondrosarcoma, with high local recurrence rate and 15% metastatic rate radiology images afip images. Nov 14, 2019 parosteal osteosarcoma occurs in the periosseous tissues. The vast majority involve the metaphysis of the femur, humerus, or tibia. A popliteal giant synovial osteochondroma mimicking a parosteal osteosarcoma. Osteosarcoma is the most common primary malignant tumor of bone in adolescents and young adults.
Twoopenbiopsies were performed, and ahistologic diagnosis of parosteal osteosarcoma rendered locally was subsequently confirmed bydr. A rare case of parosteal osteoma of the clavicle was described. Parosteal osteosarcoma pos is a unique low grade osteosarcoma. Most common type of juxtacorticalsurface osteosarcoma. Pdf parosteal osteosarcoma mimicking osteochondroma. Parosteal osteosarcoma parosteal os is the most common type of juxtacortical os, accounting for approximately 5% of all os cases and typically manifesting in. Parosteal osteosarcoma, lowgrade central osteosarcoma, and fibrous dysplasia share similar histological features that may pose a diagnostic challenge. An osteosarcoma os or osteogenic sarcoma ogs or simply bone cancer is a cancerous tumor in a bone. It has a predilection for the knee area with 50% of cases in either the distal femur or proximal tibia, with the second most common site being the proximal humerus 10%. Parosteal osteosarcoma is a very rare bone tumor with a predilection for the posterior aspect of the distal femoral metaphysis. I have recently found out that i have a bone cyst on my tibia, the pain has been going on sence oct.
We present a case and discuss the diagnostic and therapeutic implications of a rare lowgrade parosteal osteosarcoma of the maxilla. The areas of the abnormal lesional woven bone merged with the bony. Parosteal osteosarcoma pos is a slowgrowing tumor which originates from the outer layer of the periosteum and represents 65% of surface osteosarcomas 1 and in. Coamplification of cdk4, sas and mdm2 in surface osteosarcoma.
Survival rates for osteosarcoma survival rates can give you an idea of what percentage of people with the same type and stage of cancer are still alive a certain amount of. Parosteal osteosarcoma is a welldifferentiated variant of osteosarcoma that affects the surface of the bone. Approximately 8% to 25% of the cases reported in literature developed dedifferentiation, which was reported to had increase. Nov 29, 2012 we report the case of a parosteal osteosarcoma of the distal ulna, treated with wide resection without reconstruction. We report two cases mimicking an osteochondroma, radiologically and histologically and propose an explanation. Epidemiology it is the most common type of juxtacortical or surface osteosarcoma and accounts for 5% of all osteosarcomas. Predisposing factors the risk of parosteal osteosarcoma is linked to the following factors. Parosteal osteosarcoma definition of parosteal osteosarcoma. Parosteal osteosarcoma proximal humerus age 28 cancer.
A case of parosteal osteosarcoma of the tarsus of a 23yearold woman is reported. Parosteal osteosarcoma radiology reference article. Think of that menu as a roadmap to this complete guide. Radiographs would show a surface tumor with a highly sclerotic, ossifying component associated with a tumor component in which mineralization is less than in parosteal osteosarcoma. People are encouraged to talk with their health care team about the pros and cons of joining a specific study. Lowgrade central and parosteal osteosarcoma are malignancies with a lower. Parosteal osteosarcoma shows cartilaginous cap that can be confused with osteosarcoma ct or mri scan of the affected region microscopic and pathological evaluation of tissue biopsy the specimen is examined under a microscope by a pathologist, to arrive at a definitive diagnosis. Parosteal osteosarcoma is one of the most frequently misdiagnosed entities in bone and softtissue tumors. Mark gebhardt, md and kristy weber, md also available in chinese, japanese and spanish.
The diagnosis of po is made by combining the patients medical history, clinical symptoms, laboratory examination, and imaging analysis with. A malignant tumor principally composed of anaplastic cells of mesenchymal derivation. In each patient, imaging revealed a pastedon ossified surface lesion with an intact underlying cortex and no medullary involvement. This free fact sheet is available as a pdf, so it is easy to print out. A case of parosteal osteosarcoma with a rare complication of. Figures 1a and 1b anteroposterior a and lateral b plain radiographs of the right thumb showing a boneforming lesion arising from the dorsum of the thumb metacarpal. A previously performed radiotherapy for other cancer conditions the tumor may be radiationinduced. Dedifferentiation into a more aggressive lesion is frequent and usually visible on imaging as a central lytic area in a sclerotic mass. Parosteal osteosarcoma is a lowgrade, malignant, boneforming tumor that arises on the surface of bone.
It is generally a lowgrade highly differentiated tumor but has the potential to turn into a highgrade poorly differentiated tumor, even though the incidence of such conversion is very low. The most common location is on the surface of the distal femur which accounts for 4666% of the cases. Parosteal osteosarcoma arises from periosseous tissues adjacent to the cortex. The absence of cellular atypia helps to distinguish this lesion from osteosarcoma.
Parosteal osteosarcoma is the most common subtype of juxtacortical osteosarcomas, accounting for 75% of them, with a better prognosis 7. Dedifferentiated parosteal osteosarcoma of the maxilla. Os is now classified into three main subtypes parosteal, periosteal, and highgrade surface osand these are further categorized by their histologic features and histologic grade. May 25, 2016 parosteal osteosarcoma juxtacortical osteosarcoma parosteal osteosarcoma is considered separately from the rest of the osteosarcomas because it is distinctly less malignant and, therefore, has a vastly different clinical behavior. Parosteal osteosarcoma atlas of musculoskeletal oncology. It commonly presents as a slowgrowing painless lump in the posterior aspect of the distal femur. Osteosarcoma is the second most common primary malignant tumor of bone. John hunter is a professor in the department of radiology musculoskeletal section at uc davis school of medicine. This study was performed to assess the imaging findings in cases of parosteal osteosarcoma dedifferentiated into telangiectatic osteosarcoma. Parosteal osteosarcoma article about parosteal osteosarcoma. Parosteal osteosarcoma, dedifferentiated, maxilla, head and neck, chemotherapy, case report background 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 1. The stage of an osteosarcoma is based on the results of physical exams, imaging tests, and any biopsies that have been done, which are described in tests for osteosarcoma.