Confocal Microscopy

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Melanoma in skin of mouse

A sideview (x,z @ y) of mouse skin with a single larger melanoma lesion and multiple early lesions. The large melanoma is in the center at x = 100-200 um, z = 40-60 um, y = 60 um. Note the following features:

• the stratum corneum scatters light strongly at the water/skin interface (at z = 20 um)
  Specular reflectance from the irregular skin surface causes artifactual signal to enter the lens when the focus is still above the skin focused in the clear water, which is the "fuzz" above the skin surface.
   
• the epidermal layer is lighter due to weaker scattering (at z = 20-30 um)
  The epidermis is composed of cells whose nuclei are relatively non-reflective.
   
• the epidermal-dermal junction is populated by bright melanosomes whose melanin strongly scatters light (at z = 30 um)
  Note that some isolated melanosomes occur in the epidermis. Also, there are occasional early pigmented nevi (eg., x=60, z=40 @y=199).
   
• the dermis is a little more strongly scattering than the epidermis, (at z > 40 um)

The mouse was a very black mouse whose skin strongly absorbed the blue laser light (488 nm wavelength) used in this confocal microscope. So only the upper 40 um of tissue are imaged, but the underlying dermis quickly runs out of light and cannot be imaged.

Occasionally, hair follicles will disrupt the surface, presenting as dark regions that disrupt the surface (eg., x=50, @y=145).