distal limb

What are the ddx of an aggressive digit lesion

• primary neoplasia → soft tissue neoplasia (SCC)

• Secondary neoplasia → metastasis to digits from primary lung neoplasia (mostly seen in cats)

• Osteomyelitis due to bacterial infection

How do the ddx of aggressive digit lesions differ to an aggressive bone lesion elsewhere in the body?

• Aggressive bone lesions are typically osteosarcomas elsewhere in the body OR osteomyelitis due to fungal

• in aggressive bone lesions of the digits, we see soft tissue neoplasia (SCC), secondary digit lesions due to metastasis of primary lung neoplasia, or osteomyelitis due to bacterial infection

Explain lung digit syndrome in cats (pathogenesis, clinical signs, diagnostics, px)

• secondary neoplasia from a primary lung carcinoma → metastasis occurs → aggressive digit lesion forms

• Clinical signs → digit lesion noticed first

• Diagnostics → thorax rads to look for primary neoplasm

• Poor px → no amputation as other lesions quickly occur in other remaining digits

What is involved in the work up of an aggressive digit lesion?

• FNA or amputate & histo (cannot determine the cause from radiographs)

• Thorax radiographs

  • ID metastasis; do not do sx until thorax rads are taken

What are the indications for stress radiography?

• Document instability via radiographs

• See fractures that are hidden near the joint (chip, avulsion)

What view is this, what is being seen, what aspect of the joint is seen?

• stress radiography on DP view

• Opens up medial side of joint, medial intertarsal joint indicates trauma on medial side

• Fracture fragments can be seen that are not seen when the joint is not opened up

What view is this? What part of the joint can be seen?

• stress radiography lateral view of tarsus

  • Stress applied to open up dorsal aspect of tarsus

• Proximal intertarsal joint can be seen, it is unstable

What view is this? When stress is applied, what joint is opened up? Is this unstable or stable?

• lateral view of tarsus

• Stress applied to open up plantar aspect of tarsus, identifying that the proximal intertarsal joint is unstable

What view is this? When stress is applied, which joint opens up? Is this joint stable or unstable?

• DP view of tarsus

• Stress applied to open up lateral side of the joint → distal intertarsal joint visible

• No instability seen on this side of the joint

Explain how stress radiography can be performed without holding

• use sandbags or tape when doing radiographs → pull one piece of tape cranially or caudally depending on what joint you want to open up

What are common causes of aggressive bone lesions? Are they more common in dogs or cats?

• common in dogs, uncommon in cats

• Most common cause

  • Soft tissue neoplasia (SCC) - 2/3 of cases

  • Osteomyelitis from nailbed infection → 1/3 of cases (bacterial)