Abstract
The transmittal of knowledge on the morphologic characteristics of lesions has traditionally been a tedious although rewarding endeavor. The use of photographs was essential for this transmittal of information and has been widely used in books and journal publication with the limitations on the use of color photos due to production costs. Fortunately, as diagnostic pathologists we have entered a new era as characterized by the set of CDs that respectively provide color reproductions of classic lesions in the livers of rats and mice as prepared by the National Toxicology Program. The beauty of this format is the presentation of numerous color illustrations that provides not only the opportunity to view multiple types of lesions but view them in many cases at multiple magnifications. The diagnostic pathologist is acutely aware of the importance of recognition of subtle changes recognized at low magnification as a guide for necessitating additional examination at higher magnification.
The structure of presentation of material on the CD is excellent, providing easy navigation through the material available. The Home Page provides a guide through a Table of Contents at the beginning of each CD which allows the viewer to immediately focus on the type of lesion of interest e.g. congenital lesions degenerative lesions, hyperplastic and neoplastic lesions. In addition, the left side of the Home Page provides an Index which lists the specific diagnosis of lesions and specific toxicants causing various lesions so a viewer may immediately proceed to the lesion or toxicant of interest.
The quality of the photographic images is variable as might be expected with such a massive undertaking. Most are of excellent quality when viewed on a standard screen. As all pathologists have encountered, the lower magnifications are the images that are less clear. Nevertheless, the authors of the CD are to be congratulated for the inclusion of the multiple magnifications that provide the complete presentation of the respective lesions including the lower magnifications for orientation and the high magnification to provide specific diagnostic detail.
The range of lesions presented is excellent. Many of the routinely encountered liver lesions of the rat and mouse are represented including the more common occurring background lesions as well as the classic lesions that represent responses to toxic injury. The mouse CD includes lesions of the gallbladder which tend to not always be given due considerations. Since the inclusion of genetically modified mice has become increasingly important in recent years, the mouse CD has included a selection of the more commonly identified liver lesions in genetically modified mice that are being used in research and testing of drugs and chemicals. It is of course impossible to provide a complete catalogue of spontaneous liver lesions in the myriad of genetically modified mice that are being developed for broad research purposes.
The potential users who would benefit from the acquisition and reference to the 2 CD set of rodent liver lesions are numerous. The CDs provide quick reference for the morphology of lesions that may be seen less frequently by an experienced toxicologic pathologist. The greatest contribution of this set will be to the pathologist in training or the well trained pathologist who is beginning to focus diagnostic skills and expertise on the evaluation of lesions in rodents that have been part of a chemical or drug safety testing program. The availability of this quick reference material should be a part of every pathology training program that provides even rudimentary attention on rodent pathology. While the CDs are an important contribution to the field of rodent liver pathology, a potential future user should have tempered expectations. As the titles of the CDs indicate, the material is an atlas of morphologic lesions. Likewise, the authors clearly state on the Home Page that the purpose is to “… familiarize pathologists and others with the spontaneous and chemically induced lesions seen in the livers …” of rodents. They do not represent rodent liver pathology text books on CDs. While there is frequently a short statement regarding the lesion associated with each photograph or set of photographs, the information about the lesions is very limited. To effectively understand the origin and significance of the lesion, the viewer will need to utilize the material on the CDs in conjunction with specialized pathology texts and the primary literature.
In summary, the CDs on liver lesions of rodents have advanced the dissemination of information regarding lesions of rodent livers. The authors are commended for undertaking this effort and for making this material and information readily available. However, the availability of these CDs provides several challenges for the future. Obviously, similar atlases on other organs and other species used in toxicology such as the dog and monkey would provide an important contribution similar to the contribution of the currently discussed set of CDs. The availability of the image material in these CDs immediately engenders the desire on the part of the viewer for additional information regarding the lesion. Of course, this would lead to specialized pathology texts on CD taking advantage of the opportunity to combine numerous photographs with a more detailed understanding. The authors of these CDs have clearly established an expectation for expanded use of the CD format to the benefit of toxicologic pathology in the future. For complimentary copies of the CDs, contact Robert R. Maronpot, NIEHS, 111 Alexander Drive, MS B3-06, Research Triangle Park, NC 27709 or