CT of secondary neoplasms. Unusual structural features--a pictorial essay.

The newer anticancer therapies, the routine employment of cross-sectional imaging modalities for staging and follow-up, and the increased survival rate of patients with neoplastic lesions have markedly widened the range of pathological and imaging features of secondary neoplasms. Moreover, the changes occurring in morphological and structural aspects of metastases may be the direct effect of the improved therapeutic tools, and in turn may offer revealing clues to the clinician regarding the outcome of therapy itself. The scope of this essay is to show the atypical computed tomographic (CT) aspects of a series of metastatic lesions. We selected the lesions on the basis of their unusual structural features, such as calcification; hemorrhage; superinfection; pseudocystic, cystic, and lipoid appearance; and hypervascularity. A highly detailed assessment of such changes is nowadays possible and appears mandatory.