A significant percentage of cases in surgical neuropathology represent non-neoplastic lesions; these can be particularly challenging for the pathologist, both at the time of intraoperative consultation and on permanent section. The differential diagnosis is often broad and confident diagnosis in some cases requires correlation with clinical and serological data. This course will provide a practical approach for the pathologist in how to handle a variety of non-tumoral lesions of the central nervous system. The course will begin by presenting an approach to what can be confidently discerned at the time of frozen section, where the evaluation of most of these lesions begins. Using a series of cases by way of illustration, histologic findings or "flags" suggestive of a potential non-neoplastic diagnosis will be discussed and an algorithmic process will be presented on how to evaluate these lesions.

The topics to be covered include: 1) radiation and chemotherapy induced changes (gliosis versus glioma); 2) processes resulting in thickened blood vessel walls (amyloid, CADASIL); 3) chronic inflammatory processes (vasculitis, infection, lymphoma, demyelinating disease versus infarct; 4) vascular malformations (arteriovenous malformation, cavernous angioma); and 5) abscess and granulomatous inflammation.

The course will be constructed as a series of case presentations that will provide the framework for discussion. The case presentations will illustrate intraoperative consultation findings, histopathological features, differential diagnoses and utility of adjunct diagnostic modalities. Still images of each case along with histories will be posted on the USCAP web-site for review by registrants prior to the meeting. A syllabus reviewing the key points and a reference list will be provided at the meeting. All course registrants will receive Web access to the Power Point presentation presented at the meeting along with the text portion of the syllabus.

Upon completion of the course, participants should be able to: 1) recognize common pathologic features associated with certain non-neoplastic conditions; 2) differentiate between differential diagnostic considerations associated with certain patterns of injury suggestive of a possible non-neoplastic lesion; and 3) recognize scenarios which might require ancillary testing to confirm a diagnosis and know how to appropriately handle tissues at the time of intraoperative consultation. The limitations to what can be confidently diagnosed at the time of frozen or even permanent sections, based on histology alone, will be an important platform for discussion.

This course may be used for CME credits or SAM credits.