Evaluation of preputial cytology in diagnosing oestrogen producing testicular tumours in dogs

Objectives The purpose of this study was to evaluate the diagnostic sensitivity and specificity of preputial cytology in oestrogen producing testicular tumours in dogs. Methods Forty-five dogs with palpable testicular masses and 30 healthy control dogs were included. Dogs were evaluated for signs of alopecia and/or feminisation. Analyses of preputial cytology, haematology and serum oestradiol were performed. Dogs with testicular masses were neutered and the testes were submitted for histopathological examination. The dogs were divided into three groups (1) control dogs (n=30), (2) dogs with a testicular mass and serum oestradiol concentration <40 pmol/L (n=35), (3) dogs with a testicular mass and serum oestradiol concentration >40 pmol/L (n=10). Results More than 20% superficial cells in preputial smear was significantly associated with serum oestradiol concentration >40 pmol/L (P<0·001). The number of superficial cells was significantly increased (P<0·001) in preputial smears from dogs with alopecia. Clinical Significance It appears that the preputial cytology has a high sensitivity and specificity for the diagnosis of oestrogen producing testicular tumours in dogs.