Periosteal Osteosarcoma


 - See: Classic osteosarcoma

- Discussion:
    - uncommon variant of classic osteosarcoma;
    - primarily affects young adults;
    - presents as an enlarging, painless mass growing on surface of the bone;
    - most frequently seen in anterior proximal tibia & the posterior surface of the distal femur;

- Diagnostic studies:
    - large external, poorly mineralized mass w/ in a depression of cortical erosion;
    - w/ irregular margins & periosteal reaction;
    - sunburst appearance is composed of malignant cartilage and bone;
          - look for spiculed radiating mineralization;
    - diff dx:
          - classic osteosarcoma
          - periosteal chondroma
          - juxtacortical chondrosarcoma 
          - periosteal desmoid lesion:
                 - a tumor simulator;
                 - look for bone irregularity along the posteromedial aspect of the distal femur at the insertion of the adductor magnus or the origin of gastroc muscle;
                 - most commonly occurs in patients who are age 10 to 15 years;
                 - are not symptomatic (no mass, pain, or swelling);
                 - ref: Developmental defects of the distal femoral metaphysis.  


- Bone Scans:
    - bone scans show a disproportionate uptake throughout tumor, considering its predominantly radiolucent appearance;

- CT Scan:
    - CT depicts tumor lying in shallow cortical defect w/ moderate calcification;

- Histology:
    - regions of malignant mesenchymal stroma, areas of neoplastic osteoid scattered in & about lobules of low grade mature cartilage;
           - chondroid matrix may predominate in periosteal chondroma;
           - periosteal lesion will have areas of chondroid differentiation in addition to osteoid matrix;
    - normall appearing trabeculae are absent;
    - chondroblastic differentiation is seen, which by itself might indicate periosteal chondrosarcoma;
    - dx of periosteal osteosarcoma is clinched by combination of cartilage, malignant bone, osteoid and fibrosarcomatous tisse;


- Treatment and Prognosis:

    - prognosis for patients with periosteal osteosarcoma is fair.
    - extension through cortex occurs earlier than in parosteal osteosarcoma;
    - bony extension implies worse prognosis w/ higher incidence of pulmonary metastases;
    - lesion is almost always amenable to excision with a wide margin.
    - chemotherapy is indicated only for higher grade, dedifferentiated tumors;

 Osteosarcomas arising on the surfaces of long bones.

Periosteal osteosarcoma.

Periosteal Osteosarcoma: long-term Outcome and Risk of Late Recurrence.





Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Thursday, June 7, 2012 5:02 pm