Cerebral Parenchymal Lesions: I. Metastatic Neoplasms

Abstract

After one has reasonably ruled out the possibility of a nonneoplastic diagnosis (see Chap. 3), one is left with considering a diagnosis of tumor. The first question one needs to ask along these lines is whether or not the neoplasm could represent a ­metastasis. Metastatic neoplasms are the most commonly encountered tumors in the central nervous system. Because the appearance of these lesions often mimic their appearance elsewhere in the body, most pathologists are relatively more comfortable with evaluating metastases. Metastases are commonly multifocal lesions that are well circumscribed (Fig. 4.1). This is in contrast to many gliomas, which tend to be infiltrative in nature and more typically unifocal. Metastases may be either parenchymal or leptomeningeal in location.