Small Animal Radiology and Ultrasound: A Diagnostic Atlas and Text

Chapter Four The Appendicular Skeleton 531
Fig. 4-75 A 4-year-old female domestic short-haired cat with a
chronic right foreleg lameness with swelling. There is soft-tissue
swelling involving the right forelimb. An area of bony destruction
involves the proximal one half of the right radius. There is a small
amount of bony proliferation cranially and medially. The localized
nature of this lesion with massive bony destruction and little bony proliferation
suggested a primary neoplasm. A biopsy was not performed.
The leg was amputated. Diagnosis: Cryptococcosis. A destructive pattern
may occur with infections that mimic the patterns seen with a primary
neoplasm. This case exemplifies the critical role of a bone biopsy.
Fig. 4-76 A 3-year-old male
Labrador Retriever with left rear leg
lameness, a draining tract medial to
the left stifle, and a distended and
painful joint. There is soft-tissue
swelling involving the stifle joint.
There is bony destruction within the
left femur in the distal metaphysis. A
small amount of periosteal new bone
formation is present on the medial
aspect of the left femur (arrow).
There is some loss of bone density
within the patella. The diffuse softtissue
swelling and involvement of
both the distal femur and patella are
suggestive of infection. Diagnosis:
Septic arthritis and osteomyelitis.
This was due to Nocardia infection.