The problem in the image most likely occurred at which stage?

• A. Staining
• B. Embedding
• C. Sectioning
• D. Fixation

Answer: (B)

Embedding is the stage where the dehydrated and cleared tissue is infiltrated with molten paraffin to form a solid block that can be thinly sectioned. If the image shows a block with gaps, air pockets, or tissue that isn’t fully surrounded by wax, or if sections crumble or pull away during microtomy, these are classic signs that infiltration during embedding was incomplete. The tissue needs to be completely infiltrated so the paraffin supports and surrounds all parts of the specimen; otherwise, the block lacks integrity and the resulting sections are fragile or poorly oriented. Ensuring thorough paraffin infiltration, using properly heated and fresh paraffin, and correctly orienting the tissue in the mold addresses this problem.