Semeiotics of bone tumors in children.

In recent years, the study of bone disorders has changed thanks to the progressive development of imaging techniques. In our opinion, however, different from what happens in the study of pathologic conditions in other organs and systems, conventional radiology remains the diagnostic cornerstone for bone disorders and especially bone tumors. In any case, plain radiography must always be performed first. The radiologic approach to primary bone tumors includes a series of steps to collect the necessary information to suggest, with the following contribution of radiography, the most likely diagnosis. The approach is basically statistical and many parameters should be considered. As far as bone tumors in children are concerned, the basic role of the statistical variable 'patient age' is apparent and this information should be considered even before any others. Despite the difficulties in assessing the frequency of bone tumors we tried to read homogeneously some of the statistical data reported in literature. Tumor incidence in a given age class is a very important diagnostic tool. Lesion location is the second step in the radiologic work-up: the involved bone and bone segment should be assessed and correlated with the preferential site of a specific tumor. Regarding the bone tumors detected in the first 5 years of life, an interesting question is whether a vertebra plana is due to a benign or a malignant lesion. The lytic lesion will be well defined by CT and MRI will be very useful in depicting bone marrow and surrounding soft tissue involvement. However, many processes have a similar imaging pattern. We believe that before biopsy the frequent, marked infiltration of surrounding soft tissues in vertebra plana should suggest a diagnosis of malignant tumor rather than of tumor-like lesion.