What happens to an excised biopsy specimen

A specimen changes shape after excision and histologic processing.

In normal skin from six dogs, the full sampling and routine processing sequence reduced length and width but increased thickness. Length and width decreased by as much as 32%, while thickness increased by as much as 75.8%. These are roughly one-third less in length and width, and about 75% more in thickness.

These figures were the largest changes in that study, not correction factors for every specimen. They describe linear length and width, not a percentage loss of surface area. They also reflect the combined sampling and processing steps; no separate percentage was assigned to formalin alone.

References

Reimer et al. (2005), AJVR. https://pubmed.ncbi.nlm.nih.gov/15822596/