[killjoywashere]

Have you seen a dermatology textbook? They're the thickest books on my shelf. And as a pathologist, I'm only seeing the stuff that merits "I'm not exactly sure what to do here, let's get a biopsy and see if that provides us more information."

Then I, as the pathologist, provide some hedgy answer that's not in the textbook, because the patient's disease didn't read the textbook. And we have to jam that all into CPT codes, SNOMED codes, LOINC codes, ICD9 and ICD10 codes, complete with conversions between major and minor releases of those code lists, etc, etc.