The cytologic characteristics of canine AS are widely heterogeneous, but supplementary findings can provide clues that are useful for making a cytologic diagnosis. Histologic and immunohistochemical confirmation is nonetheless warranted in all cases.

The results of this study confirmed FNAC as a reliable and useful diagnostic procedure for the evaluation of palpable cutaneous and subcutaneous lesions in small animal practice.

The cytological features of 19 histologically confirmed canine ovarian tumours were retrospectively examined. Seven cases were cytologically classified as papillary adenocarcinoma, eight cases as granulosa cell tumours, two cases as mature ovarian teratomas, one case as a dysgerminoma and one case as a mixed granulosa cell tumour/dysgerminoma. On cytology, papillary adenocarcinoma was characterised by a papillary glandular pattern and tight cohesiveness. Granulosa cell tumours showed monolayered clusters of loosely cohesive granulosa cells. Call-Exner-like bodies were found in five of seven cases. Granulosa cells appeared to be heterogeneous and usually contained several intracytoplasmic vacuoles. Teratoma was characterised cytologically by keratin debris (two cases) and a mixture of epithelial cells with sebaceous, basaloid, columnar/palisading or ciliated appearance (one case). The dysgerminoma contained severely atypical round cells admixed with small lymphocytes. The mixed dysgerminoma/granulosa cell tumour had a mixture of germinal and granulosa cells. Cytological diagnosis was in agreement with histopathology in 18 of 19 (94.7 per cent) cases.

The origin of an adrenal tumor can be easily determined by cytology alone in many cases. However, cytology was not reliable in distinguishing benign from malignant neoplasia. Additional studies are needed to assess possible risks and complications associated with fine-needle biopsy of adrenal tumors in dogs and cats.