Possible parachordoma in a dog.
METHODS
A 15-mm diameter mass developed in the S/C tissue overlying the right lateral gluteal muscle of a 6(1/2)-year-old female Flat-coated Retriever.


RESULTS
Cytological preparations following aspiration of the mass were highly cellular and consisted of a population of large polygonal cells containing single to multiple nuclei, large prominent nucleoli, and intracytoplasmic vacuoles. Histologically, the neoplasm consisted of similar large cells surrounded by thick fibrous connective tissue trabeculae. The large polygonal cells reacted positively with antibodies against vimentin, low- and high-molecular-weight variants of cytokeratin (AE1/AE3), but not with antibodies to desmin or glial fibrillary acidic protein (GFAP).


METHODS
The clinical, gross, histological and immunohistochemical findings are similar to those reported for parachordomas in humans. Neither recurrence nor metastases were noted 18 months after surgical excision of the mass.


CONCLUSIONS
This is the first reported case of a possible parachordoma in a dog, a benign tumour with cytological features of malignancy.
Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand. s.f.forsyth@massey.ac.nz
S F
SF
Forsyth
K G
KG
Thompson
A F
AF
French
T R
TR
Halsey
D000818:Animals; D004283:Dog Diseases / Q000473:pathology*; D004285:Dogs; D005260:Female; D009369:Neoplasms / Q000473:pathology / Q000662:veterinary*; D012983:Soft Tissue Neoplasms / Q000473:pathology*