Fine needle aspiration cytology of pilomatricoma in three dogs.
BACKGROUND
Fine needle aspiration cytology is being used for the diagnosis of various neoplasms, but we are unaware of reports dealing with the cytologic features of canine pilomatricoma.


OBJECTIVE
The purpose of this report was to describe the cytologic features of pilomatricoma in 3 dogs.


METHODS
Fine-needle aspirates were obtained from cutaneous masses using a 25-ga needle. Smears were prepared and stained with May-Grünwald-Giemsa and hematoxylin and eosin. The cutaneous masses were excised and routinely processed for histologic examination.


RESULTS
Cytologic features of all 3 tumors included high cellularity and numerous clusters of tightly arranged of basaloid cells with evenly distributed chromatin and small distinct nucleoli surrounding sheets of "ghost cells". Ghost cells were characterized by a central unstained zone corresponding to the site previously occupied by the nucleus. Amorphous keratinized material was observed in 1 tumor. Histopathologic findings confirmed the diagnosis of pilomatricoma in all 3 cases.


CONCLUSIONS
Basaloid cells in association with ghost cells are important cytopathologic criteria that may provide a definitive cytologic diagnosis of pilomatricoma in dogs, and may help avoid a false diagnosis of malignancy.
Masserdotti
Carlo
C
Clinica Veterinaria S. Antonio, via Montale n degrees 2, 25087 Salo (BS) Italy. carsila@numerica.it
Ubbiali
Federica Annamaria
FA
D000818:Animals; D001707:Biopsy, Needle / Q000662:veterinary; D003937:Diagnosis, Differential; D004283:Dog Diseases / Q000175:diagnosis* / Q000473:pathology; D004285:Dogs; D005260:Female; D006201:Hair Diseases / Q000175:diagnosis / Q000473:pathology / Q000662:veterinary*; D008297:Male; D018296:Pilomatrixoma / Q000175:diagnosis / Q000473:pathology / Q000662:veterinary*; D012878:Skin Neoplasms / Q000175:diagnosis / Q000473:pathology / Q000662:veterinary*; D013194:Staining and Labeling / Q000662:veterinary