Canine-Orthopédique : A case of osseous lymphoma in a dog

Boxer Dog, male, 7 years old. Since few weeks, it shows weight loss, partial anorexia and lethargy.

The owners are concerned by the dog reluctancy to stand up, intermittent bilateral lameness and bad clinical condition

Clinical exam: skinny animal, normal cardiac and respiratory ausculatation. no obvious lameness detected, but the dog shows pain at manipulation of the 4 legs and of the back.

Radiography: ML projection of both hindlegs and lumbar spine
Both hocks show signs of degenerative joint diseases associated to joint effusion (more prominent on the right). this suppose that the process is active.

Bilaterally, we can see marked periosteal reaction along the diaphysis of both tibiae and metatarsal bones. This periosteal reaction is solid and smooth but also palissading at some places.

The medullary cavity of both tibiae show an increased heterogeneous opacity with a mottled appearance.

So we have a multiostotic, symetric process characterized by osteoprolifération and mild lysis diffusely along diaphysis and metaphysis.

At this level our differential can be:
- a secondary neoplastic process (mets from a prostatic carcinoma, round cell tumor like lymphoma, myeloma, eventually hemangiosarcome)
- a metabolic disease like hypertrophic osteopathy
- a fungal infection

On the thoracolumbar spine, multifocal well defined round radiolucent areas are seen in the vertebrae. These punched out lesion are not surrounded by a sclerotic rim and are typical of a round cell tumoral process like myeloma or lymphoma.

On FNA of the swollen medial iliac lymph nodes, a lymphoma was the final diagnosis.