Clinical History:

A 12-year-old boy noted pain in the left lower leg, even at night, for several months following a blow to the calf from a soccer ball. A radiograph revealed a mass lesion involving the metaphysis of the distal femur.

The cells here tend to be spindle cells as well as polygonal cells. The nuclei show marked pleomorphism and hyperchromatism. Occasional mitoses are present. Irregular new bone is being formed. Compare the bone in the neoplasm to that on the other side of the epiphysis which is normal.

Questions:

1. Patients often equate a history of trauma with appearance of a neoplasm. How often is trauma the etiology for a neoplasm?

Trauma is not considered to be an etiology for neoplasia.

2. How can you tell that this neoplasm is arising in bone? What methods are available to determine the cell of origin?

Radiographic procedures can show the location and appearance of the neoplasm and what tissues are involved. Radiographs can be correlated with the histologic appearance. If the tumor is making osteoid, then it is probably primary to bone and an osteosarcoma. Further histologic studies could include immunoperoxidase staining (such as an immunoperoxidase stain for vimentin to show a mesenchymal origin, as opposed to a stain for cytokeritin that would detect tumors of epithelial origin). Electron microscopy is sometimes helpful in distinguishing neoplasms of epithelial origin (with desmosomes), melanomas (with melanosomes), and lymphomas.

3. How is such a tumor most likely to spread?

Sarcomas typically metastasize hematogenously.


4. How does the process of informed consent work if the patient is a child?

Osteosarcoma can often be treated successfully, but it can also be treated unsuccessfully. There are different therapeutic procedures available. Thus, osteosarcoma is a classic example of the importance of informed consent, letting the patient know the chance of death even with treatment, and giving the patient all of the choices that you are willing to respect. In other words, let the patient know your recommended option is not the only option.

Osteosarcoma is often diagnosed in children, which raises further important informed consent issues. Should the child have any say in the decision? The degree of input will vary with age. A child of 1 or 2, of course, cannot have any input, but a child of 3-6 can have some input, and a child of 7-12 can express many preferences that are worth respecting, even if a child at this age can't make fully informed decisions. The American Academy of Physicians states that for teenagers (adolescents) "probably most can make decisions regarding life-sustaining treatment." This may not be true when the initial diagnosis is made, but if the child has had the disease for a while and undergone treatment already, the child may be better able to make informed decisions than parents or physicians.

This then raises the question of the extent of parental and physician rights to make decisions for children. Both have obligations to make decisions based on the best interest of the child. Thus, both have a role in making well justified paternalistic decisions. Parents are usually thought of as the first-line decision makers, but if their decisions are contrary to the child's best interest, in the opinion of the physician, then the physician's responsibility is to try and work with the parents to better understand the situation, and if that fails, to go to court to get authorization to proceed with treatment.