Full Papper Case Report
Extraskeletal Osteosarcoma
dr Nyoman Gde Aditya Gitapradita B
dr Gede Eka Wiratnaya SpOT
Department Of Orthopaedic and Traumatology
Udayana University/Sanglah Hospital
EXTRASKELETAL OSTEOSARCOMA INTRODUCTION
Estraskeletal osteosarcoma is malignant mesenchymal neoplasm that produces osteoid, bone or chondroid material without demonstrable attachment to bone or periosteum, as determined by radiographic and intraoperative examination. The diagnosis of extraskeletal osteosarcoma is very rare and represent 2% to 5% of osteosarcoma and < 1% of all soft tissue sarcomas. Males are affected more frequently than females. 1,2,4
Previous prospective studies follow of soft tissue sarcoma have not analyzed extraskeletal osteosarcoma separately, as the number of cases remains small. Most common location is lower extremity especially in thigh, followed by upper extremity and retroperitoneum mechanical injury has been hipothesized as causative agent, but the etiologic eignificance of trauma is difficult to assess. 2,3
CASE AND METHOD
Picture 1. Solid mass on medial side proximal left thigh
Picture 3. MSCT Angiography left femur, bulging solid soft tissue mass intramuscular on left proximal femur with calsification and ill define margin, without destruction to os femur and os pelvis, and no periosteal reaction
tissue mass without extend to subcutis. Os femur without destruction cortex or bone marrow intensity changes
Picture 5. Clinical Picture post marginal excision and biopsy
Picture 7. Show that mass of the tumor infiltration inside bone trabeculae
DISCUSSION
Extraskeletal osteosarcoma (EO) is a malignant mesenchymal tumour of soft tissue composed of neoplastic cells that recapitulate the phenotype of osteoblasts and synthesize bone. all EOs contain neoplastic bone but may also have cartilaginous and fibroblastic components. By the definition, extraskeletal osteosarcoma arises from soft tissue without osseous or periosteal involvement. 4, 5
Extraskeletal osteosarcoma is a rare neoplasm that accounts for 1-2% of all soft tissue sarcomas and approximately 2- 4% of all osteosarcomas. It typically arises during mid and late adulthood with most patients in the 5th-7th decades of life at the time of diagnosis. Males are affected more frequently than females at a ratio of 1.9:1. 4
The majority of EOs arise in the deep soft tissues and fewer than 10% are superficial, originating in the dermis or subcutis. The single most common location is the thigh (approximately 50% of cases); other frequent sites include the buttock shoulder girdle, trunk, and retroperitoneum. 4
EO first described by Wilson in 1941, few large series of these tumors have been reported. In 1956, Fine and Stout suggested that it may show behavior similar to primary osteogeneic osteosarcoma in the bone. As compared with osteosarcoma of bone, EOs is rare and occurs infrequently in patients under 40 years age. 2,6,7
Most patients present with a progressively enlarging mass that maybe associated with pain. By definition these tumours do not arise from bone, but may secondarily involve the periosteum, cortex or medullary canal. To be qualified as extraskeletal osteosarcoma, the tumor must (1) arise in the soft tissue and not be attached to bone or periosteum, (2) have a uniform sarcomatous pattern (to exclude the possibility of mixed malignant mesenchymal tumor), and (3) produce osteoid and/or cartilage matrix. 4,6
foci on T1-T2 weighted sequences, consistent with methmoglobin, or hypointense foci on T2 weighted sequence, consistent with hemosiderrin deposition. 7
Extraskeletal osteosarcomas range in size from 1-50 cm (mean 8-10 cm) and are circumscribed, tan-white, haemorrhagic and focally necrotic gritty masses. All of the major subtypes of osteosarcoma that arise in bone may be seen in EO. The most common is the osteoblastic variant, followed by the fibroblastic, chondroid, telangiectatic, small cell, and well differentiated types. The tumour cells are spindle or polyhedral cells that are cytologically atypical, are mitotically active and frequently demonstrate atypical mitotic figures. The bone is usually most prominent in the centre of the tumour with the more densely cellular areas located in the periphery a pattern that is the reverse of myositis ossificans. Telangiectatic EOs contain numerous large blood filled spaces lined by malignant cells. Sheets of small round cells that mimic Ewing sarcoma or lymphoma are typical of the small cell variant. The extremely rare well differentiated subtype contains abundant bone deposited in well formed trabeculae, surrounded by a minimally atypical spindle cell component similar to parosteal osteosarcoma. 7
Extraskeletal osteosarcoma, similar to its bone counterpart, was charactheristic by fully malignant, anaplastic spindle cell proliferation, with the presence of osteoid matrix or immature bone formed by neoplastic cell. Malignant condroid areas also observed in association with osteoid or bone component. Occasionally, extraskeletal osteosarcoma has been mistaken for myositis ossificans. Extraskeletal osteosarcoma can be difficult to distinguish from MFH, Fibrosarcoma and malignant schwanoma. The pathologic diagnosis is confirmed by the presence of neoplastic osteoid, with or without cartilage matrix, produced by the malignant mesenchymal cells, identical morphologically to primary osteogenic sarcoma of the bone. 2,5,6
regarding radiation and soft tissue sarcomas do not include cases of extraskeletal osteosarcoma, if specified at all. 1,5,6
Extraskeletal osteosarcoma has a very poor prognosis and approximately 75% of patients die of disease within 5 years of diagnosis. More than half of the patient have multiple recurrences and metastasis. Most local recurrences and distant metastases occur within 3 years postoperatively. Lee and colleagues, found no association between size and survivability. Therefore, a classification system that guides treatment on basis of prognostic factors is as yet unefined. Nevertheless, as metastasis is the main factor in survival rate, early diagnosis is imperative. 4,5,6
CONCLUSION
Refferences
1. Lisa E. Choi, MD et al. Analysis of Outcomes in Extraskeletal Osteosarcoma: A Review of Fifty-three Cases. Memorial Sloam-Kettering Cancer Center, New York, NY. Journal Bone Joint Surgery. 2014; 96: e2 (1-8)
2. Martin D. McCarter et al. Extraskeletal Osteosarcoma: Analysis of Outcome Of Rare Neoplasm. Memorial Sloam-Kettering Cancer Center, New York, NY. Sarcoma.2000. 4, 119-123
3. Fouzia Lateef et al. Extraskeletal Osteosarcoma. Departement of Hystophatology. Dr. Ziauddin Hospital, Karachi. Journal of the Collage of Physician and Surgeon Pakistan. 2011. Vol. 21 (7): 429-430
4. Christhoper D.M. Fletcher et al. Pathology and Genetics of Tumours of Soft Tissue and Bone. WHO. IARCPress. Lyon. 2002
5. Brian E. Welczak et al. Rare Extraskeletal Osteosarcoma in the Anterolateral Right Leg of a 37-Year-Old Man. Department Orthopaedic Surgery, Mount Clemens Regional Medical Centre, Michigan. Am J Orthop. 2009; 38(5): E93-E97
6. Joy S.Y.Lee, M.D et al. A Review of 40 Patients With Extraskeletal Osteosarcoma. Division Anathomic Pathology and the Department of Orthopaedic, Mayo Clinic and Mayo Foundation, Rochester, Minesota. 1995
