Cytologic and histopathologic evaluation of extruded canine degenerate disks.
OBJECTIVE
To describe the cytologic and histopathologic appearance of degenerate disk material in dogs with Hansen type I intervertebral disk disease (IVDD).


METHODS
Case series.


METHODS
Dogs (n=45) that had surgical intervention for Hansen type I IVDD (January-November 2007).


METHODS
Impression smears and histopathologic sections were prepared from surgically removed degenerate disk material. All slides were evaluated for overall cellularity, quantity and attributes of extracellular matrix, types of cells present, and their cytomorphology. Histopathologic sections were also examined for presence of neovascularization and hemorrhage.


RESULTS
Cytologically, 11 of 45 samples consisted of only extracellular matrix, 30 had evidence of inflammation, and 20 contained dysplastic spindloid cells. Histologically, hyaline cartilage predominated in 35 of 45 samples, fibrocartilage in 4, and spindloid cells in 6; 37 of 45 were inflamed, 37 were hemorrhagic, and 13 had neovascularization.


CONCLUSIONS
The cytologic and histopathologic appearance of extruded degenerate disk material in dogs is variable and can include dysplastic spindloid cells.


CONCLUSIONS
The variability in cytologic findings and frequent presence of dysplastic spindloid cells suggest that cytology alone may not be a reliable tool to differentiate degenerate canine disk material from a mesenchymal neoplasm.
Departments of Veterinary Pathobiology and Medicine and Surgery, University of Missouri College of Veterinary Medicine, 900 E. Campus Drive, Columbia, MO 65211, USA. royalab@missouri.edu
Angela B
AB
Royal
Munashe
M
Chigerwe
Joan R
JR
Coates
Charles E
CE
Wiedmeyer
Linda M
LM
Berent
D000818:Animals; D004283:Dog Diseases / Q000473:pathology* / Q000601:surgery; D004285:Dogs; D005260:Female; D007403:Intervertebral Disc / Q000473:pathology*; D055959:Intervertebral Disc Degeneration / Q000473:pathology / Q000601:surgery / Q000662:veterinary*; D008297:Male