A 19 y.o. pitcher presents with a sore shoulder. He describes the pain as achy and it has been going on several months.

What do you notice?

Our patient had an osteosarcoma proven on biopsy.

 Osteosarcomas are the most common pediatric and adult bone tumor, with more than 1000 new cases every year in the United States alone. 20% of individuals present with metastatic disease at the time of diagnosis with the most common site being the lungs.

calcified mets from osteosarcoma

The most common site of osteosarcoma is the leg with half of the cases involving the distal femur and proximal tibia. The patient often presents with pain in the area of the tumor.  Xrays  are key but can be subtle in the early stages.  Codman’s triangle is the name given to a periosteal reaction  with an aggressively growing tumor that lifts the periosteum off the bone as it grows. New bone may be seen under the periosteum forming the triangle.

Codman’s triangle

Tumors can present with a “sunburst pattern” representing ectopic bone production as shown below. which can be subtle in the early stages.

The image appears brighter on the R due to ectopic bone production.

There are several factors associated with osteosarcoma including prior irradiation, bone infarcts and bone abnormalities like Paget’s disease. Genetic abnormalities have also been identified as in hereditary retinoblastoma.

As the tumor progresses typical findings include lytic lesions and pathological fractures.

Treatment of osteosarcoma generally involves surgery and chemotherapy. Doxorubicin and cisplatin with or without methotrexate often are the initial chemotherapeutic agents. Current belief is that  osteosarcoma is initiated by cells along the mesenchymal  lineage  and influenced by tumor suppressor genes like P53 . Recurrent or metastatic disease is extremely hard to treat making the early diagnosis important.

Our patient is awaiting surgery.

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Abarrategi A., Tornin J., Martinez-Cruzado L., Hamilton A., Martinez-Campos E., Rodrigo J.P., González M.V., Baldini N., Garcia-Castro J., Rodriguez R., et al. Osteosarcoma: Cells-of-Origin, Cancer Stem Cells, and Targeted Therapies. Stem Cells Int. 2016;2016:1–13. 

Albuquerque J, Marchiori E, de Macedo F. Pulmonary metastasis of osteosarcoma: multiple presentations in a single patient. J Bras Pneumol. 2022 Apr 6;48(2):e20210478tuhl’

McDonald J, DenOtter T. Codman triangle . StatPearls

Tang F, Min L, Zhou Y, et al. Low-grade central osteosarcoma in proximal humerus: a rare entity. Onco target Ther. 2017 Oct 24;10:5165-5172.