Cutaneous Pathology (dermatopathology) is the microscopic examination of skin biopsies in order to determine a specific diagnosis or a list of differential diagnoses. Usually the diagnosis can be determined by the routine stain for tissue sections (Hematoxylin and Eosin). Hematoxylin is a basic stain that stains basophilic structures such as chromatin and ribosome's a deep purple or blue. Eosin is an acidic stain that stains acidophilic structures red. The advantage of this stain is that it provides a clear stain of the cell nuclei; it provides a good stain for the cell membrane. These stains are not as specific for the tissue it stains. Nonetheless, this stain aided pathologists in diagnoses. In addition to hematoxylin and eosin, the pathologist may use additional special stains to narrow a differential diagnosis or confirm an initial impression and one of these is immunohistochemistry. Immunohistochemistry has become an important technique and widely used in many medical research laboratories and is dependent on the localization of antigens in tissue sections by the use of labeled antibody as specific reagents through antigen-antibody interactions that are visualized by a marker such as peroxidase.