Case of the week 5.28.19
Publication Date: 2019-05-28
History
9 year old Bernese Mountain dog. Lame for the last two months
2 images
Findings
Orthogonal radiographs of the carpus are available for interpretation.
There is a large soft tissue opaque mass surrounding the distal metaphysis of the right radius and ulna. The margin of this mass is undulating at its medial aspect. There is columnar to spiculated periosteal proliferation along the medial, cranial, and caudal aspect of the distal third of the diaphysis of the radius. There is permeative to motheaten lysis of the distal third of the diaphysis and distal metaphysis of the right radius with sclerosis, and a long ill-defined transition zone. There is mild thinning of the cortex of the distal metaphysis of the ulna. The trabecular pattern of the accessory carpal bone is more coarse than expected. No additional abnormalities are identified.
Diagnosis
The mass associated with the distal right antebrachium is most consistent with a neoplastic process, and may represent a soft tissue sarcoma invading bone, or a periosteal osteosarcoma of the distal right radius. The changes to the distal ulna and accessory carpal bone are likely artifactual less likely neoplastic invasion can't be totally excluded.
Discussion
FNAs of the mass were performed and were consistent with histiocytic sarcoma.
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