This section consists of three main titles: Thoracic, Hepatobiliary, and Urogenital Malignancies. In each section, the most common malignancies are discussed under subheadings. The spectrum of pediatric lesions differs from that of adults. Age is also an important criterion for the diagnosis of lesions in children. It should also be noted that lesions associated with genetic diseases or infections, as well as proliferative and hamartomatous non-neoplastic lesions, are common in this period. Imaging modalities provide useful information for tumor characterization, staging, and treatment planning. Common malignant tumors in each section have been reviewed with radiologic case examples.