Elsevier

The Veterinary Journal

Volume 205, Issue 2, August 2015, Pages 322-327
The Veterinary Journal

Diagnostic value of cytological analysis of tumours and tumour-like lesions of the oral cavity in dogs and cats: A prospective study on 114 cases

https://doi.org/10.1016/j.tvjl.2014.10.022Get rights and content

Highlights

  • Cytology was compared to histopathology for the diagnosis of masses of the oral cavity of dogs and cats.

  • FNI in dogs showed the highest sensitivity and specificity for oral tumours.

  • In cats all methods had high sensitivity and specificity for oral lesions.

  • Cytology is appropriate to correctly diagnose lesions of the oral cavity in dogs and cats.

Abstract

Neoplastic or non-neoplastic masses are common findings in the oral cavity of cats and dogs. The aim of this prospective study was to compare the results of cytological examinations of lesions of the oral cavity following fine-needle aspiration (FNA), fine-needle insertion (FNI), and impression smear (IS) with histopathological results being considered as the diagnostic gold standard.

In total, 85 dogs and 29 cats were included in the study. Cases were included when histology and cytology (FNA, FNI, and/or IS) were available from the same lesion; κ-agreement and accuracy between cytological and histopathological results were calculated. Eighteen cytological specimens were excluded, with a retrieval rate of 84.2%. Of the 96 samples analysed, FNA, FNI, and IS were available from 80, 76, and 73 animals, respectively. Overall, 60/67 (89.6%) and 21/29 (72.4%) lesions were neoplastic in dogs and cats, respectively, with the remaining being non-neoplastic. For all lesions, κ-values obtained by FNA, FNI, and IS were in dogs 0.83 (95% confidence interval [CI]: 0.77–0.90), 0.87 (95% CI: 0.81–0.93) and 0.75 (95% CI: 0.67–0.84), respectively, and in cats 0.92 (95% CI: 0.87–0.96), 0.92 (95% CI: 0.88–0.97) and 0.86 (95% CI: 0.79–0.92), respectively. The diagnostic accuracies of FNA, FNI, and IS in dogs with neoplasia were 98.2%, 98.1%, and 91.8%, respectively, and in cats with neoplasia were 95.6%, 95.6% and 95.8%, respectively. In conclusion, the high agreement with histopathology suggests that cytological examinations by FNI, FNA, and IS are all appropriate methods to correctly diagnose lesions of the oral cavity in dogs and cats.

Introduction

Masses in the oral cavity are commonly observed in dogs and cats, with a large variety of diagnoses spanning from benign and malignant tumours to tumour-like conditions (Spodnick, Page, 1995, Goldschmidt, Hendrick, 2002). The most frequent oropharyngeal cancer in dogs is melanoma (Smith et al., 2002), and the majority of these are malignant (Bradley et al, 1984, Spodnick, Page, 1995), whereas the most common oral neoplasm in cats is squamous cell carcinoma (SCC) (Bradley et al, 1984, Spodnick, Page, 1995, Liptak, Withrow, 2006). SCCs account for 70% of feline and 25% of canine oral neoplasms and may arise from virtually any surface of the oral cavity (Bradley et al., 1984).

Cytological examination is a minimally invasive diagnostic tool that is routinely used in companion animal medicine. The results of cytology correlate well with histopathological findings for many tumours (Bonfanti et al, 2006, Ghisleni et al, 2006, Simon et al, 2009) including angiosarcoma, mammary tumours, and osteosarcoma in dogs (Allen et al, 1986, Bertazzolo et al, 2005, Reinhardt et al, 2005, Simeonov, Stoikov, 2006, Simon et al, 2009, Sontas et al, 2012), as well as thymoma, lymph node and splenic lesions, and abdominal, cutaneous or subcutaneous masses in dogs and cats (Ménard et al, 1986, Rae et al, 1989, Chalita et al, 2001, Bonfanti et al, 2004, Ghisleni et al, 2006, Ovejero Braun, Hauser, 2007). However, the diagnostic reliability of cytology in the evaluation of oral masses has not been previously investigated in dogs and cats.

In humans, only a few reports have explored the diagnostic potential of fine-needle aspiration (FNA) for oral lesions and for lesions of the maxillofacial region. Nonetheless, the limited information available supports the clinical utility of cytological analysis, with a sensitivity ranging from approximately 75% to 96%, and a specificity and positive predictive value reaching almost 100% (Cramer et al, 1995, Singh et al, 2011).

The aim of this prospective study was to determine the diagnostic reliability compared to histopathology of cytology obtained by FNA, fine-needle insertion (FNI; non-aspiration technique), and impression smear (IS) from masses of the oral cavity of dogs and cats.

Section snippets

Criteria for selection of cases

Dogs and cats with masses of the oral cavity examined at the authors' institutions (MG, GR and WB) between 2007 and 2010 were included. Most animals were from the northern part of Italy and were referred to large clinics in this region. Cases were included when cytological and histopathological specimens were available from the same lesion.

Procedures

From oral cavity lesions, cytological specimens were obtained by FNA and FNI using different gauge needles (21–25 G) and 2.5–5 mL syringes for aspiration.

Animals and samples

A total of 114 animals were initially recruited for the study, including 85 dogs and 29 cats. The dogs consisted of 39 intact males, 25 intact females, 12 spayed females, and 9 neutered males. The median age of dogs was 9 years (range, 1–17) (Table 1). The cats included were 13 spayed females, 10 neutered males, 3 intact males, and 3 intact females. The median age of cats was 11 years (range, 1–17 years) (Table 2).

Oral lesions

Of the 114 animals, 110 (96.5%) had a single oral lesion and 4 (3.5%) had

Discussion

The reliability of a diagnosis obtained from a biopsy specimen of an oral lesion is critical in veterinary oncology. Biopsies provide information that is necessary to select the most appropriate treatment protocol (e.g. surgery, radiation therapy, or chemotherapy) and to decide on the extent of the treatment, either conservative or aggressive. The results of this study demonstrated high agreement and accuracy between FNA, FNI and IS in diagnosing canine and feline oral cavity lesions when

Conclusions

The high agreement with histopathology and accuracy observed with FNA, FNI, and IS suggest that cytological examination of oral cavity lesions is an effective procedure in dogs and cats. Because cytological examination performed with either FNA or FNI allows for immediate evaluation, may not need anaesthesia, and is cost effective, these methods may represent the first diagnostic approach of tumours of the oral cavity in dogs or cats.

Conflict of interest statement

None of the authors of this paper has any financial or personal relationships with other people or organisations that could inappropriately influence or bias the content of the paper.

Acknowledgements

Preliminary results were presented as an Abstract at the 13th Annual Meeting of the European Society of Veterinary Clinical Pathology and the European College of Veterinary Clinical Pathology, Trinity College Dublin, Dublin, Ireland, 31 August–3 September 2011.

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