About Arizona Carcinoid & Neuroendocrine Foundation, Inc.
During the late 1940s, Dr. Theodore Woodward at the University of Maryland School of Medicine coined the phrase, “when you hear hoofbeats, think horses not zebras.” The intent was to have his interns make independent diagnoses without resorting to the concept of some exotic disease that might make an impression during their studies. Since there are more horses than zebras in the United States, this statement maintained a strong relevance to the beginning stages of diagnosis. Gradually the statement gained wide acceptance in the medical community. Several rare diseases, including neuroendocrince cancer, claimed the zebra as a mascot, to highlight the flaw in this method of diagnosis. Diagnosticians have noted; however, that the “zebra” type diagnosis must nonetheless be held in mind until the evidence conclusively rules them out (“Zebra Medicine,” Wikipedia 2015). In making the diagnosis of the cause of illness in an individual case, calculations of probability have no meaning. The pertinent question is to ask whether the disease is present or not. Whether it is rare or common does not change the odds in a single patient. If the diagnosis can be made on the basis of special criteria, then these criteria are either fulfilled or not fulfilled (Harvey, A. M. et al., 1979).