Seven of these were excluded from further analyses: five low-grade osteosarcomas (three low-grade central and two parosteal
), one osteosarcoma occurred as a secondary malignancy (following B-cell lymphoma), and one benign bone lesion originally misdiagnosed as osteosarcoma, leaving 23 patients with primary high-grade osteosarcomas for statistical analyses (Table 1).
The most frequent one is the t(3;12)(q27-q28;q14-q15), which is recurrent in lipomas (of soft as well as parosteal
tumor) and fuses LPP with HMGA2 .
Leithner et al., "Bizarre parosteal
osteochondromatous proliferation (Nora lesion): a report of 3 cases and a review of the literature," Canadian Journal of Surgery, vol.
Conventional lipomas can arise in subcutaneous tissue (superficial lipoma), in deep soft tissue (deep lipoma) or on surface of bone (parosteal
MDM2 Positivity by IHC and FISH in Soft Tissue and Bone Tumors Tumor Type MDM2 by MDM2 by IHC FISH ALT/WD liposarcoma + + (nuclear) Dedifferentiated liposarcoma + + (diffuse, nuclear) Pleomorphic rhabdomyosarcoma - + Intimal sarcoma + + (up to 70%) Malignant peripheral nerve sheath tumor - + (subset) Myxofibrosarcoma - + (subset) Low-grade central osteosarcoma + + Conventional osteosarcoma + (10%) - Parosteal
osteosarcoma + (>85%) + Undifferentiated high-grade pleomorphic + (17%) - sarcoma of bone Abbreviations: ALT/WD, atypical lipomatous tumor/well differentiated; FISH, fluorescence in situ hybridization; IHC, immunohistochemistry; MDM2, mouse double minute 2 homolog; +, positive; -, negative.
Extraskeletal LGO displays histologic features resembling those of a parosteal
osteosarcoma but without adipose component nor connection with the underlying bone .
Types (histologic subtypes) of osteosarcoma include intramedullary (osteoblastic, chondroblastic, fibroblastic, small cell, telangiectatic, high-grade, low-grade central), surface (parosteal
, periosteal, high-grade), and extraskeletal variants.
We think that the cause of this at the initial period of regeneration is presence of massive parosteal
and periosteal calluses closely attached to the surrounding soft tissue with good vascularization and incomplete development of endosteal callus.
osteosarcoma of the mandible I J Oral Maxillofac Pathol 2006; 10(1)10-14.
The remaining 2 patients had histological diagnoses of periosteal osteosarcoma and dedifferentiated parosteal
Multiple bilateral parosteal
bone and callus forma- tions of the femur and left innominate bone.