Joseph Junewick, MD FACR
over 7 years ago
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Joseph Junewick, MD FACR
|Diagnostic Category: Neoplasia Malignant
|Created: over 6 years ago
|Updated: over 5 years ago
11 year old female with limp and knee pain.
CR – Mixed lytic and blastic distal femoral lesion with “sunburst” periostitis.
MR – Infiltrative T1-hypointense and T2- and postgadolinium- hyperintense lesion involving the diaphysis, metaphysis and epiphysis of the distal femur.
NM – Methylene disphosphonate avid lesion with no evidence of skip or metastatic lesion.
Pathology – Specimen sectioned in the coronal plane confirming the transphyseal extension of tumor.
Osteosarcoma is the most common non-lyphomproliferative malignancy in adolescence. It is derived from bone forming mesenchymal cells and can differentiate toward fibrous tissue, cartilage or bone. The presence of osteoid is necessary for the pathological diagnosis. Most commonly occurs between 5 and 25 years, with peak during adolescent growth spurt.
Osteosarcoma can be localized or metastatic. Hematogenous metastatic disease is most common at diagnosis. Regional lymphatic spread is relatively rare and carries a worse prognosis. Staging of osteosarcoma is based upon the TNM stage as well as the histologic grade. Histologic grade is based on the most poorly differentiated portion. Overall five year survival is 41%. With complete surgical resection and no metastases it is 60-70%.
Osteosarcoma is managed by a combination of surgery and chemotherapy. Neoadjuvant and adjuvant chemotherapy is used. Complete surgical excision is necessary for long-term disease control. Limb-sparing resections are less morbid, but have a slightly greater recurrence rate. The tumor is relatively radioresistant and radiotherapy is reserved for inoperable or partially resected tumors.
Classic plain film radiographic findings include a permeative intramedullary mass with cortical destruction, periosititis, and soft tissue mass. MR findings vary based upon mineralization. Highly mineralized regions of tumor have low signal on both T1 and T2 images. Less mineralized portions have intermediate signal on T1 and high signal on T2 especially soft tissue masses. Tumor enhances on post contrast images. MR should be performed to evaluate extent of tumor and relationship to vessels and nerves. Scintigraphy can be used for metastatic surveillance and recurrent disease. CT is used to evaluate for pulmonary metastatic disease.
Junewick JJ and Shreve P. Clinical PET-CT in Radiology. PET-CT in Pediatric Malignancies. Springer (2011).
Eric Payne, MD