The cancer patient with sneezing and/or nasal discharge

5 The cancer patient with sneezing and/or nasal discharge


Nasal neoplasia accounts for 1% of tumours in dogs, is considered less common in cats and has also been reported in rabbits. Therefore, although not particularly common in general practice, such cases can generate a diagnostic challenge for practitioners due to the difficulty in directly visualizing the tumour mass. The prevalence of tumour type varies between dogs and cats (dogs: epithelial > mesenchymal > lymphoid; cats: lymphoid > epithelial >mesenchymal; see Box 5.1) and the clinical signs that nasal cancer patients present with can also vary. However, in the majority of cases the clinical signs will be gradually progressive, meaning that patients presenting with recurring or worsening clinical signs warrant further or repeated evaluation. The increasing availability of advanced imaging modalities such as MRI and CT scanning have improved our ability to make accurate and early diagnoses, so the referral of patients to suitably equipped specialist centres with clinical signs that may be attributable to nasal tumours should be considered if possible.




CLINICAL CASE EXAMPLE 5.1 – CANINE NASAL ADENOCARCINOMA








Diagnostic evaluation


The dog was anaesthetized and an intraoral radiograph was suggestive of the presence of a soft-tissue mass (Fig. 5.2). The dog was then given an MRI scan, which clearly showed the presence of an intranasal tumour as shown in Figure 5.3.




A complete blood count and whole blood clotting time had been assessed and found to be normal before the diagnostic imaging procedure, so whilst remaining under anaesthesia, rigid biopsy forceps were used to obtain several pieces of the tumour for histopathology as shown in Figure 5.4. The histopathology returned to show the mass was an adenocarcinoma.



The dog underwent external beam radiotherapy using a hypofractionated course (i.e. one treatment a week for four consecutive weeks) as described. His clinical signs totally resolved by the third treatment and he remained clinically well for 12 months. He then began to develop unilateral serous nasal discharge again from the right nostril which rapidly progressed to frank haemorrhage and he was euthanized image months after the signs returned.



Theory refresher


Canine nasal tumours are most commonly seen in middle-aged to older dolycephalic dogs but can occur in any breed. Nasal tumours in young dogs would be considered unusual. Medium- to large-breed dogs are more commonly affected and there is some evidence to suggest a possible increase in incidence in dogs living in an urban environment. The initial clinical signs usually involve intermittent unilateral nasal discharge (Fig. 5.5) that progresses over a period typically of 2–3 months to a serosangeous discharge and/or frank epistaxis that may also become bilateral. Occasionally the first presenting sign will be unilateral or bilateral epistaxis or simply a swelling in the region of the nares, nasal planum or frontal sinuses but these signs would be less common as a primary presenting problem. In cases where the tumour is located in either the frontal sinus(es) or the caudal aspect of the nasal cavity, the presenting complaint may initially be considered as a neurological condition (presenting with dullness, depression, head pressing or possibly seizures) but again this would be a less frequent appearance. More commonly, many owners will report that the dog has developed loud snoring or a gurgling sound when asleep and sneezing is also commonly reported. Otherwise many patients will appear normal to their owners in the early stages of the disease.







Biopsy


Direct visualization of a mass may also be possible using either a flexible or rigid endoscope. Identification of a mass via any imaging modality, however, does not generate a specific diagnosis, so tissue biopsy for histopathology is always required for definitive diagnosis. Cytological analysis of nasal wash fluid frequently fails to produce adequate samples and therefore this technique should not be relied on as the sole means of diagnosis and is a practice the authors now rarely use, although it can occasionally prove to be useful. Biopsies can be obtained using flexible endoscopic biopsy forceps (although these only produce small tissue samples), cup forceps or a Volkman spoon. When obtaining biopsies it is essential to ensure the tip of the biopsy instrument is not advanced beyond the medial canthus so as to avoid penetrating through the cribiform plate into the cranial cavity. Obtaining these tissue samples will result in haemorrhage that may seem significant, but this usually stops within a few minutes. It is recommended to assess the platelet count and a whole blood clotting time as a minimum data base before undertaking a nasal biopsy procedure.


Sep 10, 2016 | Posted by in SMALL ANIMAL | Comments Off on The cancer patient with sneezing and/or nasal discharge
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