Conjunctival Biopsy - Preparing the Specimendica

Conjunctival tissue is thin and flimsy. If you merely place it into fixative, it will curl. If it fixes in a curled configuration, it may be difficult for your pathologist to assess margins properly.

Step 1. Keeping the specimen flat

Place the specimen on an absorbent mount (filter paper or the inner paper wrapping of your surgical gloves -- if the paper is absorbent and not waxy).

Spread the specimen on the mount until some moisture from the tissue runs into the mount (only about 10 - 15 seconds)

Place the specimen into a vial of fixative (formalin), mount-side down.

 

The tissue has been placed on a flat absorbable mount and is being placed into a container filled with fixative.

Step 2. Indicating margins

Do not paint the margins of a conjunctival biopsy with methylene blue or toluidine blue (these dyes are aqueous based and will "bleed" into the sample).

 

The surgeon made two mistakes in preparing this specimen. First, the margins were painted with a blue aqueous-based dye which bled into the specimen -- the whole piece of tissue is colored blue! Second, the surgeon tossed the specimen into fixative without taking precautions to keep it flat. The sample is permanently curled and it is difficult to evaluate this tissue for adequacy of surgical margins.

It may be useful to tag a margin with a suture, indicating which margin is tagged on the pathology requisition form (e.g., suture through the nasal margin).

More information about conjunctival biopsies