Possible parachordoma in a dog

Authors: Halsey TR, French AF, Forsyth SF, Thompson KG
Publication: New Zealand Veterinary Journal, Volume 57, Issue 5, pp 299-302, Oct 2009
Publisher: Taylor and Francis

Animal type: Companion animal, Dog
Subject Terms: Clinical pathology, Diagnostic procedures, Neoplasia, Oncology, Pathology
Article class: Clinical Communication

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Abstract: CASE HISTORY: A 15-mm diameter mass developed in the S/C tissue  overlying the right lateral gluteal muscle of a 6½-year-old female  Flat-coated Retriever.  
PATHOLOGICAL FINDINGS: 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).  
DIAGNOSIS: 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.  
CLINICAL RELEVANCE: This is the first reported case of a possible  parachordoma in a dog, a benign tumour with cytological features of  malignancy.  
KEY WORDS: Chordoma, parachordoma, physaliferous cells, soft-tissue  tumour   
 

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