Skeletal muscle biopsy is commonly employed in the evaluation of neuromuscular disorders. This course focuses on proper technical processing of skeletal muscle biopsy specimens and the recognition of normal and diseased skeletal muscle, with a focus on commonly encountered pathologic entities. The course is targeted at pathologists in training and practicing pathologists. Proper handling of muscle biopsy specimen in order to ensure optimal histologic sections and staining and to minimize artifacts will be discussed. Specific approaches to the evaluation of a variety of pathologic entities, including differential diagnosis, will include the following general categories of muscle disease: 1) inflammatory myopathy (paticularly polymyositis versus dermatomyositis versus inclusion body myositis); 2) neurogenic atrophy; 3) drug induced myopathy; 4) muscular dystrophy; and 5) metabolic myopathy (including mitochondrial myopathy and glycogen storage disease). Particular attention will be given to the utilization of ancillary diagnostic studies including electron microscopy, genetic/molecular analysis, and enzyme/protein assays when required for the proper evaluation of a particular entity. At the end of the course, participants should be able to: 1) properly handle and process muscle biopsy specimens in order to maximize diagnostic capability and 2) recognize and be able to evaluate pathologic entities commonly encountered in skeletal muscle biopsies. Registrants will receive a CD-Rom of representative images and a detailed syllabus with references.