Page 167 - Canine Lameness

­eferences 139

Golden Retriever, Labrador Retriever, and Rottweiler (Schultz et al. 2007; Klahn et al. 2011; Manor
et al. 2018). Prior joint disease is associated with increased risk of developing periarticular histiocytic
sarcoma in dogs (Manor et al. 2018). Whereas myxomas are identified by their unique histo -
logic appearance, immunohistochemistry with CD 18 or CD204 is required to distinguish histio-
cytic sarcoma from synovial cell sarcoma (Craig et al. 2002). Other types of sarcomas (malignant
fibrous histiocytoma, fibrosarcoma, and undifferentiated sarcoma) have also been rarely
reported from the synovium in dogs (Craig et al. 2002). Although neoplastic cells can at times be
identified with joint fluid analysis, this is not a reliable method to diagnose tumors that involve the
joint capsule in the author’s experience. FNAs and biopsies are preferred to make a definitive
diagnosis.
Villonodular synovitis (also called pigmented villonodular synovitis; PVNS) has been described
in all of the major joints, including the carpus (Hanson 1998). PVNS is considered a benign neo-
plasia (Dempsey et al. 2018); however, the etiology is still not fully understood. The condition
causes proliferation of synovial tissues resulting in lameness and pain (Akerblom and Sjostrom
2006). PVNS has most commonly been described as a monoarticular condition; however, a dog
with bilateral stifle PVNS has been reported (Marti 1997). Diagnostic imaging is generally nonspe-
cific, requiring histopathology to establish the diagnosis. Even though PVNS is extremely rare, it
should be considered as a differential diagnosis when diagnostics are inconsistent with more
commonly observed conditions.

References

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Britt, T., Clifford, C., Barger, A. et al. (2007). Diagnosing appendicular osteosarcoma with ultrasound‐
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Dempsey, L.M., Maddox, T.W., Meiring, T. et al. (2018). Computed tomography findings of pigmented
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