A definitive diagnosis may be made by fine needle aspiration of the mass under ultrasound guidance or closed biopsy, but is more likely to be confirmed by thoracotomy. (randhurstanimalhospital.com)
It is a cancer that is very difficult to diagnose using fine needle aspiration cytology. (vetspecialists.com)
Diagnosis is with fine needle aspiration which is a technique for taking a biopsy of the lymph nodes to check for cancer spread and examination of the skin. (cat-health-guide.org)