The sinusoids of the liver contain several cell types including:
- Endothelial cells (cells that line blood vessels)
- Kupffer cells
- Stellate cells (also referred to as Ito cells)
These cells are difficult to distinguish on routine microscopy of normal livers. Kupffer cells are basically macrophages (cells that eat and digest) and sometimes accumulate cellular debris. This debris includes lipofuscin and iron, and as a result, may stain with periodic acid-Schiff (PAS) and/or iron stains. Stellate (Ito) cells are the site of storage for vitamin A in the liver and can become readily visible in patients with vitamin A toxicity.