KCC was challenging this week! Here are the highlights from some of the cases.
Case 1
7 year old Golden Retriever with hind limb lameness. On the thoracic radiographs, there were multiple healing rib fractures involving both sides at different levels. There were also lytic areas in the dorsal spinous processes of the vertebrae and in the humerus. Spinal technique radiographs were requested and showed the lesions more clearly. Radiographic diagnosis: Polyostotic aggressive bone lesions. Differential Diagnosis: multiple myeloma or plasma cell tumor, metastatic disease. Diagnosis: Multiple myeloma with pathologic rib fractures.
Question: Would the lesions appear “hot” on scintigraphy? Many primarily lytic lesions do not show up on a bone scan as they do not incorporate the radionuclide. That said, it may depend on inflammation and microenvironment of that particular tumor. The pathologic fractures should show increased activity because of the callus around them.
Another good point was that traumatic rib fractures are usually on the same side and at the same level. Pathologic fractures are often randomly distributed.
Here is a case with very similar lesions.
Case 2
12 year old Terrier with tetraparesis and ataxia. There was a mass effect in the left abdomen, and a lot of discussion as to where it might be coming from. Differentials included spleen, left kidney, mesenteric lymph nodes, and extraskeletal osteosarcoma. The key to this case was “find your friends”. The dorsal extremity of the spleen is visible lateral to the fundus. There is no normal left kidney, and the descending colon is displaced to midline. Additionally, there is no retroperitoneal space visible on the lateral radiograph (should be in a dog of this body condition). Radiographic diagnosis: This is a retroperitoneal, left renal mass. Differentials: primary or metastatic renal neoplasia, mineralized cyst, abscess. Check the case for the final diagnosis.
One comment I liked about a systematic approach was to read an abdominal radiograph like you are doing an ultrasound. That way you look at every organ including the ones you can’t usually see on radiographs.
Great cases! Thanks for the links to images of the cases or similar ones. Does the mineralization of the renal mass in Case 2 put neoplasia higher on your list of differentials? KC
I’m glad you enjoyed the cases! The mineralization is a bit unusual in a renal origin tumor, but that and the mass make it likely to be neoplastic. Something like a mineralized hematoma would be lower on the list of differentials.
AZ