Zipf's law applies to the diagnoses rendered in a pathology department. I helped write an early paper wherein three years' worth of surgical pathology reports, for a a university-associated hospital, were collected and reviewed.
There were 64,921 diagnostic entries (averaging 1.6 SNOMED codes per specimen and 1.4 specimens per patient), that were accounted for by 1,998 different morphologic diagnoses. A mere 21 diagnostic entities accounted for 50% of the code occurrences. 265 entities accounted for 90% of the code occurrences, indicating that the diagnostic efforts of pathology departments are primarily devoted to a small fraction of the many thousands of described pathologic entities.
This paper, published in 1994, is available for review
-Jules J. Berman
In June, 2014, my book, entitled Rare Diseases and Orphan Drugs: Keys to Understanding and Treating the Common Diseases was published by Elsevier. The book builds the argument that our best chance of curing the common diseases will come from studying and curing the rare diseases.
I urge you to read more about my book. There's a generous preview of the book at the Google Books site.
tags: common disease, orphan disease, orphan drugs, genetics of disease, disease genetics, rules of disease biology, rare disease, pathology, anatomic pathology, medical nomenclature