Diagnostics

LA Neoplasia podcast – overview; ~19 min

Signalment can help identify some tumors (eg most are more prevalent in older horses, melanomas are common in gray horses). Options for identification include visual identification (obviously not 100% accurate but often pretty good), fine needle aspirate, surgical biopsy or removal and submission for histopathology. Neoplasia should be considered with fever of unknown origin. Inflammation may or may not be detectable on physical examination. Ultrasound can be useful to determine if the mass is invading tissues and to identify the level of vascularity. Necropsy is a diagnostic tool but doesn’t do much to help that animal.  Because we are dealing with larger animals that permit minor procedures with standing sedation, an incisional or excisional biopsy often is the most productive. Remember to try to include some normal tissue in your biopsy so that the interaction between normal and diseased tissue can be assessed. Sedation with xylazine or detomidine and a local block is often sufficient to obtain these biopsies.

Treatment in food animals is restricted to methods that do not affect the food supply. Any drugs must have appropriate withholding. Laser therapy, cryotherapy and surgical removal are the primary treatment methods available. Most cattle are culled.