The diagnostic approach depends on the child's symptoms, and on a thorough examination by a general practitioner. The general practitioner will often take supplementary blood tests and sometimes X-rays, but usually will refer the child directly to a pediatrician if the child's symptoms give suspicion of a serious illness.
If the physical examination of the child and the blood tests cause suspicion of cancer, further testing will be planned accordingly. If there is suspicion of leukemia, a bone marrow examination is performed while the child is under general anesthesia.
Tumors are always diagnosed from biopsies, and biopsies must be carefully planned. Before performing the biopsy, the tumor is examined by imaging using X-ray, ultrasound, CT, and MRI to determine the localization, size, and extensiveness of the tumor.
The medical work-up of metastasis is customized for the type of tumor, and sometimes includes plain X-rays, CT of the lungs, ultrasound of the abdomen, a bone marrow examination, and also a CNS work-up with MRI or examination of spinal fluid.
Evaluation for a brain tumor is done using MRI. In small children, the MRI must be performed under general anesthesia. Brain tumors almost never metastasize outside the central nervous system, however, the most malignant brain tumors can spread via spinal fluid to other parts of the brain or bone marrow. In such cases, an MRI of the spine must be done and sometimes a bone marrow evaluation.