TY - JOUR
T1 - Parosteal osteosarcoma with a manifestation of subperiosteal low-grade central osteosarcoma
AU - Ishihara, Shin
AU - Kohashi, Kenichi
AU - Kuboyama, Yusuke
AU - Nakashima, Yasuharu
AU - Oda, Yoshinao
N1 - Funding Information:
We greatly appreciate Koji Sagiyama, a skeletal radiologist. He reviewed this case with us and assisted to describe radiological findings.
Publisher Copyright:
© 2021, ISS.
PY - 2021/9
Y1 - 2021/9
N2 - We report the peculiar case of a parosteal osteosarcoma arising beneath the periosteum in a 12-year-old boy. He complained of difficulty in left knee flexion. Plain radiography showed a uniformly dense mineralized mass in the bone cortex and parosteal ossified nodules at the metaphysis and diaphysis of the left distal femur. Periosteal reaction was not evident. Uniquely, plain radiography had a smooth outline and revealed gradually thickening mass toward the center. Histologically, the tumor showed a proliferation of spindle-shaped cells with parallel-oriented dense bone trabeculae and hyaline cartilaginous tissue disclosing mild atypia. The periosteum was inverted along the polypoid mass, but there was no periosteum at the top. Immunohistochemically, the spindle cells, including those at the top of the polypoid mass, and cartilaginous cells were positive for MDM2 and CDK4. MDM2 gene amplification was detected in these cells by fluorescence in situ hybridization. Despite the peculiar feature of plain radiography, the lesion was diagnosed as parosteal osteosarcoma. This case report presents a case of parosteal osteosarcoma arising beneath the periosteum, although it is postulated to arise in the outer layer of the periosteum. The unique radiographic findings in this case suggest an association of parosteal osteosarcoma with vigorous bone growth before closure of the growth plate.
AB - We report the peculiar case of a parosteal osteosarcoma arising beneath the periosteum in a 12-year-old boy. He complained of difficulty in left knee flexion. Plain radiography showed a uniformly dense mineralized mass in the bone cortex and parosteal ossified nodules at the metaphysis and diaphysis of the left distal femur. Periosteal reaction was not evident. Uniquely, plain radiography had a smooth outline and revealed gradually thickening mass toward the center. Histologically, the tumor showed a proliferation of spindle-shaped cells with parallel-oriented dense bone trabeculae and hyaline cartilaginous tissue disclosing mild atypia. The periosteum was inverted along the polypoid mass, but there was no periosteum at the top. Immunohistochemically, the spindle cells, including those at the top of the polypoid mass, and cartilaginous cells were positive for MDM2 and CDK4. MDM2 gene amplification was detected in these cells by fluorescence in situ hybridization. Despite the peculiar feature of plain radiography, the lesion was diagnosed as parosteal osteosarcoma. This case report presents a case of parosteal osteosarcoma arising beneath the periosteum, although it is postulated to arise in the outer layer of the periosteum. The unique radiographic findings in this case suggest an association of parosteal osteosarcoma with vigorous bone growth before closure of the growth plate.
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U2 - 10.1007/s00256-021-03747-2
DO - 10.1007/s00256-021-03747-2
M3 - Article
C2 - 33704522
AN - SCOPUS:85102514945
SN - 0364-2348
VL - 50
SP - 1903
EP - 1907
JO - Skeletal Radiology
JF - Skeletal Radiology
IS - 9
ER -