It is obviously beyond the scope and expertise of this article to cover surgical techniques but suffice to say that oral soft tissues (e.g. buccal mucosa, gingiva, fauces) are prone to crush artefact and some lesions are very friable.  If sampling is not undertaken with care, crush artefact can preclude a conclusive diagnosis.  It is also important to bear in mind that surface lesions may only be the “tip of the iceberg” such that biopsy alone may not be sufficient, but best undertaken in conjunction with imaging, to assess deeper tissues and bone. Where possible, multiple samples should be taken to ensure the biopsies are as representative as possible.  Samples should be submitted in 10% neutral buffered formalin. Oral lesions should be sampled intraorally so that lip tissue remains intact (may be required later for reconstruction)¹.    

Radical tumour resection from the oral cavity is likely to involve sampling and/or removal of bone. Most of the larger oral samples we receive originate from referral practices, since this typically requires specialised surgical techniques.  If submitting these types of samples, bear in mind that a period of decalcification will be required and this can be prolonged, depending on sample size, location and signalment of the animal (e.g. maxilla from an adult male Rottweiler will take much longer to process than a pathologically softened mandible from a cat).  We further dissect most of these samples at the laboratory but even small or thin portions of bone require a period of softening prior to cutting with the microtome. 

Particularly if orientation is not obvious – and bear in mind samples change consistency, colour and even shape during fixation – it can be very helpful to add orienting sutures or surgical ink to margins and areas of interest.  Sending photographs of the lesion in situ and following resection is also very useful to the pathologist. Where possible, it is best to avoid using thermal cautery as this can create significant artefact and hamper margin evaluation.