May 2014 Small animal case

May 2014

Cat

Female intact

15 Years of age

Presented for lameness from left

At the clinical examination, a severely swollen digit was noted and radiographs of the region were taken.

Radiographic examination

Mediolateral ( ML, left image) and dorsopalmar ( DP, right image) of the front left distal digit. 

Radiographic findings

  • There is severe soft tissue swelling around the third digit with irregular borders (arrows).
  • There is a complete loss of definition of the distal part of the third phalanx, only the proximal part of the ungual crest still visible (arrowhead).
  • The pattern of lysis is permeative.
  • The diagnosis was aggressive bone lesion in the distal phalanx of the third digit front left, with severe soft tissue swelling, likely ulcerated.
  • The list of the differential diagnosis is malignant neoplastic process primary or metastatic and much less likely osteomyelitis.
  • Radiographs of the thorax for met check were recommended.

Radiographic findings

Close up of the DP view of the distal front left limb.

Radiographic examination

Right lateral projection of the thorax (left lateral and VD not shown)

Comments

  • In the thorax, there is a well defined approximately 1cm in size soft tissue opacity in the caudal lung field, superimposed to the caudal vena cava.
  • This soft tissue opacity is mild heterogenous: has multiple pinpoints mineral opacities in the ventral half and a more lucent central area.
  • "Feline ‚lung-digit syndrome‘ decribes and unusual pattern of metastasis that is seen with various types of primary lung tumors, particularly bronchial and bronchioalveolar adenocarcinoma. Tumor metastasis are found at atypical sites, notably the distal phalages of the limbs; the weightbearing digits are most frequently affected, and multiple digit and multiple limb involvement is common. Often primary lung tumores in cats are not detected because of clinical signs referable to the primary tumor; rather, many cases present with signs referable to distant metastases. Other sites of metastases from feline primary lung tumores include skin, eyes, skeletal muscle and bone, as well as multiple thoracic and abdominal organs. These lesions are thought to arise from direct arterial embolisation from the tumor." Goldfinch et al. Journal of feline medicine and surgery, 2012
  • The digit was amputated and fine needle aspiration yield the diagnosis of carcinoma.