What is a Pathologist? Medicine is made up of many specialties. Most of us know you see a cardiologist for a heart problem, a dermatologist for skin problems and a gynecologist for women’s health issues. When then, do you see a pathologist? Maybe never, but they see you. Pathologists are physicians who diagnose and treat patients through laboratory medicine. When your cardiologist orders blood tests, a pathologist reviews the results for abnormalities; when your dermatologist removes a skin lesion for biopsy, a pathologist decides if it is cancerous; and when your gynecologist does a Pap test, a pathologist determines the result of the slide.