The lesional tissue, i.e. dysplastic epithelium, is seen on the left of the image and characterized by:

• Nuclear hyperchromatism (i.e. dark purple nuclei) - that extends to the surface,
• Nuclear crowding (i.e. nuclei are bunched-up),
• Elliptical/cigar-shaped nuclei and loss of goblet cells/reduction in the number of goblet cells.

Normal colonic type epithelium is seen on the right of the image and characterized by small round nuclei and abundant goblet cells.

The subtle vertical lines (most notable overlying the neoplastic tissue) are an artifact of the tissue preparation.

The same case:

• 
  Low mag.
• 
  Intermed. mag.
• 
  High mag.

Another case:

• 
  High mag.