Osteosarcoma: Review of the Various Types with Emphasis on Recent Advancements in Imaging

Abstract

Osteosarcoma is the classic malignant osteoid-forming bone tumor. The typical clinical presentation, histology, imaging findings, treatment, and prognosis for each subtype of osteosarcoma is provided. Particular emphasis is placed on more current magnetic resonance imaging and nuclear medicine imaging techniques that may soon improve the ability to determine the most appropriate therapy and ultimately improve patient survival.

Review of Osteosarcoma and Current Management

“…These tumors represent the classic form of OS: a high-grade mass of malignant mesenchymal cells with osteoid production and local tissue invasion. Conventional osteosarcomas are further classified into osteoblastic, chondroblastic, or fibroblastic types, depending on which matrix-producing cells dominate, but generally behave similarly in regards to appearance and prognosis [54]. Other high-grade central osteosarcomas include telangiectatic, giant cell-rich, small cell, and epithelioid variants, each with characteristic histology and small differences in survival [55].…”

“…Other high-grade central osteosarcomas include telangiectatic, giant cell-rich, small cell, and epithelioid variants, each with characteristic histology and small differences in survival [55]. A low-grade intramedullary type termed low-grade central osteosarcoma (LCOS) has a much lower rate of metastasis and greater overall survival [54, 55]. …”

“…The most common of these juxtacortical lesions is parosteal sarcoma, which constitutes about 1–6% of all OS cases [54]. These lesions are found on the metaphyseal regions of long bones, typically the distal femur, and have a “stuck on” appearance.…”

Osteosarcoma

“…This mass is usually mineralized, which is characteristic of osteosarcoma. Interestingly, after chemotherapy, this soft tissue mass usually demonstrates increased ossification [40,41]. The amount of bony destruction makes patients susceptible to pathologic fracture, and up to 15-20 % may demonstrate a fracture at the time of diagnosis [42].…”

Mesenchymal Stromal Cells Promote Tumor Progression in Fibrosarcoma and Gastric Cancer Cells

“…Tsukamoto et al9 reported MSC-associated tumor progression in a rat osteosarcoma model, and Xu et al10 described the effects of human MSCs (hMSCs) on human osteosarcoma progression. Osteosarcoma, defined as malignant neoplasm showing evidence of malignant bone formation, is very heterogeneous in terms of differentiation, genetic profiles, and clinical behavior 11,12. Fibrosarcoma is the least differentiated type of mesenchymal malignancy and is defined as a spindle cell malignant neoplasm lacking any line of specific differentiation,13 which implies that it has the least heterogeneous characteristics among the sarcomas.…”