Ophthalmic histopathology

ROUTINE AND OPHTHALMIC HISTOPATHOLOGY
Sampling Advice - General Considerations

Please complete the submission form including the animal's full signalment, a complete clinical history and your clinical impression/differential diagnoses. For histopathology specimens, please indicate whether the tissue is an excisional biopsy.
This information will ensure correct interpretation of the pathologist's findings. All specimens should be labelled with at least the
name of the animal and the owner so that identification of the specimens can be verified.

Routine Histopathology

Tissue should be fixed in 10% neutral buffered formalin. The optimal ratio of tissue to formalin is 1 part tissue: 10 parts formalin.

Handle tissue with care to avoid compression or stretch artefacts.

If the tissue to be submitted is thicker than 1cm, incisions can be made into the tissue to allow penetration of the fixative. However, please do not section all the way through the tissue as this will interfere with orientation and margin evaluation. Please leave the lateral and deep margins intact.

If the tissue sample is physically too large to send in its entirety, one or more representative sections (< 1cm thick) should be submitted. If margins are a concern, the section(s) should be taken from the narrowest surgical margin. The remainder of tissue can remain in fixative at the practice so that further sections can be submitted if necessary.

Please note that samples containing bone will require decalcification prior to processing which will delay turnaround time depending on the size of the sample. In most cases, however, any surrounding soft tissue involved in the lesion will be evaluated routinely and an interim report will be given.

All specimens should be securely packaged. The tissue should be submitted in a wide-mouth, screw-top and leak-proof container (NOT glass). The container must be wrapped in absorbent material and placed in a sealable plastic bag prior to posting in an envelope.


Ophthalmic Histopathology

Whole globes

Please complete our ophthalmic histopathology submission form. The lesions of interest can be recorded on the diagrams provided and this will aid their localisation by the pathologist. A good history is invaluable and contributes to the final interpretation of gross and histopathological findings.

Trim away excess extraocular tissue unless it is affected by the disease process as this aids penetration of the fixative. Extraocular tissue includes eyelids, fat, glandular tissue and muscle. Please do not trim away extraocular tissue if you are sending in tissue for which you require surgical margin assessment e.g. excision of an orbital mass or if the lesion is contained within the extraocular tissue itself.

eye sample
 

The intact globe should be fixed as quickly as possible to prevent dessication. In addition, the retina is prone to rapid autolysis following enucleation and this can be worsened by delayed fixation.

The globe should be fixed intact. Do not incise the globe as this leads to collapse and distortion. It is also not necessary to inject the fixative into the eye and you can create artefact in doing so.

For the majority of ocular diseases, fixation in 10% formalin is more than adequate using a volume ratio of 10:1. If necessary, the globe can be fixed in the appropriate volume of formalin for 24 hours and then placed in a smaller volume for posting.  To detect subtle retinal disease, the use of Davidson’s solution is preferred since it penetrates the sclera quickly and is ideal for retinal preservation.  A globe should only be fixed in Davidson’s solution for 24-48 hours after which it must be transferred to 10% formalin prior to sending. Bouins fixative is no longer recommended as it can be explosive under certain conditions.

This is a case of a conjunctival melanoma  - an example of when you do not want to trim off the extra-ocular tissue!

 

 



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Ophthalmic histopathology