Modern therapeutic strategies in the last decade have radically changed the approach to the oncologic patient with metastatic disease. Not infrequently today metastases are managed more aggressively and addressed in a multidisciplinary way with extremely encouraging results in terms of both survival and disease control. There have been equally revolutionary changes in diagnostic imaging, with renewed attention to early diagnosis of both local and distant recurrence, in order to prompt timely radical intervention. The distribution of metastases is affected by characteristics of the primary improved survival of neoplastic patients and the routine imaging follow-up have resulted in greatly increased detection of metastatic malignancies with less than typical appearance and behaviour. Modern therapies have radically changed the approach to the patient with metastases, creating new challenges for the radiologist. Beyond the early diagnosis of cancer, there is a new attention toward early diagnosis of recurrence. Accurate assessment of disease extent and its morphostructural features (calcification, cavitation, hemorrhage, infection) have become crucial in the evaluation of the response to treatment. Cross-sectional imaging is exquisitely suited for this task. The publication provides the practicing radiologist with a systematic and analytical tool to address the polymorphous aspects of metastases on CT, with a prarticular emphasis on their modalities of diffusion, structure and more or less usual localizations.

1 Pathogenesis of the Metastatic Process

2 Modalities of Metastatic Diffusion
Lymphatic Diffusion
Lymphangitic Infiltration
Hematogenous Diffusion
Neoplastic Seeding
Perineurial Diffusion
Neoplastic Thrombosis
Lepidic Diffusion
3 Structural Features of Metastases
Calcified Metastases
Pseudocystic Metastases
Cavitation of Metastases
Cystic Metastases
Hemorrhagic Metastases
Lipoid Metastases
Infected Metastases
4 Anatomical Sites of Metastatic Colonization
Classical Targets
Rare Sites of Metastases
Appendix 1 Bizarre Metastases
Appendix 2 Differential Diagnosis Tables
References.