Which statement about shrinkage in tissue processing is true?

• A. Sections processed by the cellodin method show less shrinkage than sections processed by the paraffin method.
• B. Sections processed by the paraffin method show less shrinkage than sections processed by the cellodin method.
• C. Both methods produce the same amount of shrinkage.
• D. Shrinkage is not affected by the processing method.

Answer: (A)

Shrinkage during tissue processing is influenced by the embedding medium and the dehydration/clearing steps. The paraffin method requires aggressive dehydration to absolute alcohol, followed by clearing with a solvent like xylene and infiltration with hot paraffin. This sequence removes water and lipids more abruptly and can cause tissues to contract and distort, leading to greater shrinkage.

Celloidin embedding uses a resin in ether-alcohol and infiltrates tissue more gradually with gentler solvent exchanges, providing better mechanical support as it hardens. This gentler process reduces the abrupt loss of water and structural collapse, so the tissue retains more of its original size.

So, sections processed by the celloidin method show less shrinkage than those processed by the paraffin method. Shrinkage is not the same for all processing methods, and paraffin tends to cause more shrinkage due to its harsher dehydration and clearing steps.