What are the broad criteria to distinguish bening from malignant tumours?
List three benign skin tumours and two malignant skin tumours commonly encountered in veterinary practice.
Benign: canine cutaneious histiocytomas, hair follicle tumors in dogs, hemangiomas, lipoma, melanomas (mostly benign)
Malignant: hemagniosarcoma, mast cell tumor, lymphosarcoma