tailieunhanh - Ebook Biopsy interpretation of pediatric lesions: Part 2

(BQ) Part 2 book "Biopsy interpretation of pediatric lesions" presentation of content: Central nervous system and skeletal muscle, hematopoietic system, the heart, the lung, pancreas, adrenal, thyroid, parathyroid, and selected head and neck, breast and reproductive system, skin. | 6 CENTRAL NERVOUS SYSTEM AND SKELETAL MUSCLE Peter Pytel, MD Most pediatric biopsies encountered in general practice are of lesions in the central nervous system. In some instances, however, biopsies sampling peripheral nerves, skeletal muscles, or peripheral ganglion cells are received. These latter biopsies are often referred for specialized processing and are only discussed briefly in this chapter. Most of the chapter focuses on CNS tumors and their mimics, which are discussed separately even though the practicing pathologist will consider both of these in the differential diagnosis of any given case. CENTRAL NERVOUS SYSTEM TUMORS In absolute numbers, pediatric central nervous system (CNS) tumors are relatively rare, but proportionally, they represent the most common solid neoplasm occurring in the pediatric age group. They are a very diverse group of tumors complicating the classification as well as the study of these –3 Children more commonly present with infratentorial tumors in contrast to adults in whom tumors are more often supratentorial. As in adults, the anatomic location is a key consideration in the process of making a diagnosis (Table ). In many cases, the received specimen does not provide any clues for determining the anatomic location of a tumor, and in many institutions, the specimen requisition forms lack detail beyond a generic description of “brain tumor.” The neuroradiology images, therefore, provide critical information for the pathologist. Pediatric CNS tumors are classified according to the World Health Organization (WHO) The assigned WHO grade describes the biology of the lesion, but a low grade does not always imply a good outcome. In this classification system, pediatric tumors are stratified according to the same criteria as those used for adults. As discussed in the following section, there are some limitations to this approach. Tumors classified as glioblastoma in children may, for .