In a dermatopathology laboratory, grossing personnel and histotechnologists must have a general understanding of skin morphology to make sound decisions that assist in the diagnosis. Since most skin pathology occurs in the dermal-epidermal junction, distinguishing and maintaining the integrity of these skin layers is critical. The following few sections focus on the various cells and structures that make up the layers of human skin.
Epidermis:
- Outer layer and protective surface of the skin
- Stratified squamous epithelium (keratinocytes) that generates keratin and melanin
- Has 5 layers made up of differentiating keratinocytes
- The basal layer rests on the basement membrane, which is next to the dermis
- Melanoma, basal cell, and squamous cell carcinomas originate in the epidermis
Dermis:
- Elastic layer just beneath the epithelial basement membrane
- Contains collagen and elastic tissue, blood vessels, nerves and sensory receptors, hair follicles
- Skin cancer may proliferate into this layer
Subcutis (hypodermis):
- Just beneath the dermal layer
- Comprised of adipose (fat) and blood vessels
- Shock absorber and thermal insulator
- This layer may be affected by skin cancer as well
The image identifies all the layers and structures within each layer of skin.
