Rubbish In, Rubbish Out: Getting the Most Out of Pathology
American Association of Zoo Veterinarians Conference 2019
Mary Duncan, BVMS, PhD, DACVP, MRCVS
Saint Louis Zoo, Saint Louis, MO, USA


You submitted a biopsy or cytology sample and receive back a report stating “non-diagnostic sample,” and it is probable that the pathologist muttered “rubbish in, rubbish out.” My goal is to improve the level of diagnostic reports you receive.

Rubbish In

Take the sample at the border of the lesion with normal tissue (center of the lesion is likely necrotic, organisms are most commonly seen at the interface). Submit a picture of the lesion prior to surgery with the biopsy. Invite the pathologist to view. Images and inks are helpful for sample orientation.

Tiny biopsies taken from the gastrointestinal tract should be placed on a foam pad in cassette, folded in lens paper, to create “teabags.” Separate out left and right, stomach pylorus, and antrum into separate cassettes if precise location is important.

Carcasses should be placed under refrigeration as soon as possible (not frozen). If tissue is severely autolyzed (e.g., reptile under heat lamp, furry mammal died overnight in summer heat), histology may not be worthwhile and possibly an unnecessary expense.

Euthanasia solution will cause discoloration and alteration in consistency of tissues; generally the affected tissue is not of diagnostic quality.

Why Do a Necropsy Anyway?

Pesky cases may finally make sense. The cause of death may be identified, and other problems might come to light. It provides a review of the anatomy. Necropsies are way more fun than doing budgets. At an Association of Zoos and Aquariums accredited institution, you are required to conduct necropsies.

What Samples Should I Collect at Necropsy?

Is a specific protocol available for the species? Species Survival Plans may provide information. If you’ve never done a necropsy on a fill-in-the-blank species, where should you begin?

Keeping things together. Use jars (left and right) and bouffant surgery caps.

How Should I Save My Samples?

There are available fixatives that vary in benefits, pros and cons, length of storage, and safety of use. Ideally for good fixation, a sample should be only up to 1 cm in dimension. Frozen samples can include multiple small pieces.

Follow a Routine

A submission protocol should be followed. Cases for necropsy should be submitted with some background information, including identification (e.g., prosector will check against bands, notches), origin, status, history (e.g., it is helpful to know if the animal was under treatment, was anorexic), weight, radiographs, natural death or euthanized (if euthanized, the method and route).

A log book should be maintained, either hard copy or electronically. Keep a cheat sheet; take pictures (particularly if you have a team involved on a large case), so no one person will get to see everything (e.g., text pictures).

Bank tissues. In collecting samples, you are going to collect a routine list to bank; this allows you to build up a collection of normals for comparison to lesions. Likewise, if one of a pair of organs looks normal, you will still collect tissue for comparison.

Necropsy On-site, Away from Necropsy Room

Keep a checklist so you can pull equipment together quickly (e.g., extension cords, barrels).

Write a Report

More important than the jargon, the detailed descriptions written in the present tense, is that you get some kind of report entered as soon as possible after the necropsy, since the longer you leave it the poorer your recall (cheat sheets will help). This is of particular importance when there has been a team effort on a large case (you may even want to designate a scribe), when different people may take the lead on different body systems. Make a rough copy and have others add their input before a final gross report is circulated.


Speaker Information
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Mary Duncan, BVMS, PhD, DACVP, MRCVS
Saint Louis Zoo
Saint Louis, MO, USA

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